Found on nearly every street corner in the city and most pizzerias throughout the United States, New York's thin, gas-cooked rounds are what many Americans think of when they think of pizza. These classic pies and individual slices are both crisp and chewy, ideal for folding in half and gobbling up on the go. Grab one at Joe's Pizza in Greenwich Village. The small shop moved a couple of blocks from its original location in 2005 and has debuted three additional outposts, but it still serves the same iconic slices with bright sauce and gooey cheese that it has since 1975, at just $3 a pop.

Neapolitan pizza is serious business. The style has its own certification, Verace Pizza Napoletana (VPN), from an organization that specifies which ingredients, equipment and pizza-making methods can be used. Ribalta is one of the two VPN-designated pizzerias in New York City. It allows its dough (just flour, water, salt and natural yeast) to mature for at least 72 hours before it's coated with a sauce of imported tomatoes and Buffalo mozzarella and tossed in an 800- to 900-degree wood-burning oven for 60 to 90 seconds. It gets just a sprinkling of fresh basil when it comes out. That strict method of preparation results in a puffy exterior crust, called a cornicione, with a nice crunch, as well as a flavorful center that droops down with bright sauce and salty cheese.

Since 1905, when Gennaro Lombardi started slinging America's first coal-fired pies in his namesake Little Italy pizzeria, New York City has been known as a coal-pizza town. Three of Lombardi's acolytes opened their own iconic coal-oven shops — John's, Patsy's and Totonno's — and all are still firing pies today. Each drew from the tenets of Neapolitan pizzerias, searing thin crusts in scorching ovens and topping them with a generous spread of fresh mozzarella and San Marzano tomato sauce. But these pies have a thinner crust and crisper bottom and, like most foods in the U.S., come in a bigger portion than their Italian predecessor. Try one at this Coney Island institution, where the pies created with daily-made, never-refrigerated dough are sold to adoring fans until the day's batch has sold out.

There are two things most people tend to know about Sicilian pizza: It's square, and it has a thick, crumbly crust. Before it hits the oven, the dough is proofed for a long time to give it a light and airy texture with a nice crumb. Though it's one of the least popular styles of pizza in New York City, it's one of the best when done well. L&B has been creating Sicilian converts since 1939. The three-in-one Bensonhurst pizzeria, restaurant and ice cream shop's rectangular pies retain their springy crust by using a layer of gooey mozzarella as a buffer between the dough and the sweet, garlicky tomato sauce. The whole crimson sheet gets sprinkled with salty flakes of Parmesan.

It might look like a Sicilian, and it, too, is stretched in a pan with olive oil, but the grandma pie is a marvel all of its own. Actually made by Italian nonnas at home, the dough for these square pies isn't proofed as long as for their fluffier, rectangular counterparts; this results in a thinner, denser base with a crisp, olive oil-infused crust. The homestyle pizzas are said to have originated on Long Island before spreading to New York City and through the rest of the tri-state area. That's why many who want a taste of this style choose to make the pilgrimage to the island where it was born, at Umberto's of New Hyde Park. The thin square is topped with a rich and vibrant oregano-infused tomato sauce, and creamy, oven-crisped mozzarella cheese.

Deep-fried Neapolitan-style dough began popping up in the New York-New Jersey area in the mid-aughts and has since spread throughout the rest of the United States. Of course it did — who doesn't love the idea of fried dough topped with red sauce and cheese? The Montanara is the most-popular pick at Forcella in Brooklyn. There, the dough is flash-fried to create a light and airy crust before being layered with San Marzano sauce, mozzarella, Parmesan and basil, and then taking a trip through the wood-fired oven. That last step helps dry the oil from the golden dough that creates something strangely reminiscent of a savory doughnut...that's also a pizza.

Way better than the stuff that comes out of a grocery freezer or your pantry, French bread pizza is a college-student staple in Ithaca, New York. The pizza-sandwich hybrid, known as the Poor Man's Pizza (PMP), was invented by Bob Petrillose in the 1960s at his late-night food truck, the Hot Truck. Petrillose patented the dish and in 2000 sold the business to his friend Albert Smith, then-owner of Shortstop Deli. Today the deli is where you can find French bread pizza 24 hours a day, seven days a week. Each Hot Truck Pizza (yes, a third moniker) is made fresh to order with tomato sauce and mozzarella on a third of a loaf of pillowy Ithaca Bakery French bread. It's baked open-face until crisp with a choice of toppings, then folded over so it can be consumed on the midnight slog home.

This New England specialty isn't for everyone, due to its enthusiastically spiced sauce and its often dense, overly bready crust. Regular pizza dough is infused with olive oil and stretched out into an oil-coated steel or aluminum pan, where it's topped with a chunky, oregano-heavy tomato sauce, piled with grated cheddar and mozzarella cheese and baked in a 500-degree oven. These golden rounds tend to be found at places with words "pizza house" or "house of pizza" in the name. The best example is from George's Pizza House in Harwich, Massachusetts. There, the thick crust is perfectly chewy on the inside and so crisp on the exterior it almost seems like it's fried, cracking into small pieces as soon as you bite in.

Grilled pizza, which has become a backyard staple in recent years, was invented in Providence, Rhode Island, back in 1980 by Johanne Killeen and George Germon, the husband-and-wife chef-owners of Al Forno. The pies at this iconic Italian restaurant are still just as good as they were at the time of their creation — and they've become even more of a staple. Quickly proofed dough with a high gluten content is soaked in light olive oil and pressed by hand before it's coated with toppings and cooked directly on the grill grates above maple charcoal. The boomerang-shaped crust ends up crisp and chewy, charred with pockmarks. Toppings range from traditional margherita with two kinds of cheese to corn with spicy olive oil and crispy calamari.

This Rhode Island specialty, sometimes referred to as bakery-style pizza or tomato pie, is a staple at Italian bakeries in the Ocean State. It varies from place to place, but it's basically made in a way that blends the processes of grandma and Sicilian pies. Focaccia dough is spread out on large rectangular trays and topped with tomato sauce before it goes into the oven. When it comes out, the crimson squares are sprinkled with Parmesan, cut into strips and sold at room temperature by the strip or tray. These garlicky, peppery bands have been on the menu at D. Palmieri's Bakery in Johnston since Domenic Palmieri opened the doors more than 35 years ago and are by far the most-popular item sold at the shop.

Like New York Neapolitan pies, New Haven apizza is a direct descendant of renowned pies of Naples, Italy. But unlike New York's historic pies, these rounds are the product of a long, cold dough fermentation that gives the crust a more nuanced flavor and chew. It then picks up even more flavor and crunch from a turn in a scorching coal-fired brick oven, which imbues the crust with the style's signature char. That's exactly how Sally's Apizza in New Haven, Connecticut, has been making its famous pies — so beloved by Frank Sinatra that he regularly sent his driver 60 miles from Manhattan to pick them up — since 1938. Its tomato pie is a work of art, with a tangy housemade sauce made from a proprietary blend of tomatoes and fresh herbs, with no cheese in sight.

In coastal towns along the New Jersey, Delaware and Maryland shores, there's a style of pie that's considered a summertime must. It's called boardwalk-style pizza, a thin-crust pie covered with a mozzarella-cheddar blend and tomato sauce swirled on top. That's how it's done at Grotto Pizza, a Delaware classic that has spread out from its Rehoboth Beach beginnings. Because it's made with the cheese right on the dough, followed by the twirl of slightly sweet sauce, each bite offers a different experience. A sauce-heavy mouthful is sweeter and tangier, and the cheesier pieces are flakier and buttery, making a slice an ever-changing pizza party for the palate.

The Garden State is hailed for its juicy, flavorful tomatoes, so it's not exactly a surprise that one of its regional pizzas focuses on the sauce. It's the star of the Trenton Tomato Pie, a crisp round covered with cheese and toppings, finished with a vibrant red sauce. That's the gist at Classico Tomato Pies, whose namesake dish was dubbed the best tomato pie in the state by USA Today. The year-old restaurant's pie is hailed for its soft, lightly blackened crust and ample cheese placed directly on the dough, followed by bright crushed tomatoes, seasonings and oil as well as diverse toppings — familiar ones like eggplant and hot peppers and less expected ones like pork roll and jalapenos.

Stretched and baked in sheet pans, Philadelphia tomato pie bears a close resemblance to Sicilian pizza, with a 1-inch-thick crust made from pan-proofed dough. But that's where the similarities end. These room-temperature bakery-made squares are made from a focaccia-type dough topped with a thick and sweet tomato gravy, with no toppings or cheese — aside from a light dusting of Romano or Parmesan. Grab a slice at fifth-generation-owned Sarcone's Bakery in South Philly. The Italian shop, now run by Louis Sarcone, still uses the same recipe for its rich, super-sweet sauce and light, chewy crust that Louis' great-grandmother developed back in the day.

Old Forge, a northeastern Pennsylvania town five miles from Scranton, calls itself the "pizza capital of the world." The town does boast quite a few pizzerias for its population of around 8,000 people. Its eponymous style, baked in rectangular trays, has a pale white crust, a rich onion-infused tomato sauce and an unusual array of cheese blends that sometimes include varieties like American and cheddar. Hidden away in a residential neighborhood, Mary Lou's makes some of the best Old Forge pizza in town. Octogenarian owner Mary Lou Verdetto and her grandson Joe make fresh dough every morning to use up by the end of the day. Her crisp crust is lighter and fluffier than most of the other spots, with an ideal balance of onions and sweet tomatoes. As a result, the plain red trays are often ordered in advance by adoring fans.

For Washington, D.C.'s late-night revelers, bigger is better. The city has its own regional pizza variation that's distinguished by size more than style, called the D.C. Jumbo Slice. The staple was created in the funky nightlife haven Adams Morgan and has spread throughout the city. A favorite among folks who need to soak up booze after a night on the town, each of these extra-large New York slices is about the size of a human head — hey, just look at the picture. Duccini's Pizza is the place to indulge. Each 13.5-inch long piece has a crispy crust with an appropriate balance of fresh mozzarella and marinara. They go for $5 a pop — $6 if you want to add some pepperoni.

In Steubenville, Ohio, and other Ohio River towns, local pizzerias dole out square pies covered with piles of cold — uncooked — grated cheese. Known as Ohio Valley-style pizza, these crisp-crust pies come out of the oven with just a coating of tomato sauce and are then covered with fresh cheese and often pepperoni. Each bite is warm, cool and crunchy all at once. While the square pies can now be found throughout the region, the style started at DiCarlo's in 1945. To this day, the shop (which now has dozens of family-owned and franchise spinoffs) uses the same crunchy Italian bread dough, whipped tomato sauce and aged provolone that helped cement the specialty as a regional icon.

Brier Hill pizza — a pan-cooked round covered with a thick sauce, bell peppers and Romano cheese — is so popular in the Youngstown, Ohio, area that when Pizza Hut opened its doors here, the chain felt compelled to add it to the menu. Some of the earliest examples were made for a fundraising project at St. Anthony's Catholic Church, and visitors can still get a taste there every Friday evening. To get these distinctive pies throughout the week, however, Wedgewood Pizza in Austintown is the place to go. Its flavorful rounds have a crisp golden-brown crust topped with all of the expected Brier Hill accoutrements.

Basically a hybrid of Sicilian pizza and deep dish, Detroit-style pizza was born in 1946 when Gus Guerra decided to bake a pie in a blue steel pan that was originally designed for the auto industry. That tray essentially acted like a cast-iron skillet, creating a nice thick crunch on the exterior of the crust. A thick layer of mozzarella and brick cheeses coats the dough, and a layer of sauce is added to the top to ensure a perfectly crisp crust. You can still get those pies at the original Buddy's, but Loui's in Hazel Park is another top Detroit-style player. Entering the unrenovated restaurant is like walking into a time warp, with all the Chianti bottles hanging from the ceiling, checkered tablecloths and old-school kitsch that was totally in vogue when Loui's opened its doors in the 1970s.

Ever since Pizzeria Uno filled its thick crust with cheese and other toppings in 1943, deep-dish pizza has become synonymous with the Windy City. But it's not exactly an everyday thing. "Deep dish is our Times Square," says Steve Dolinsky, author of Pizza City, USA: 101 Reasons Why Chicago Is America's Greatest Pizza Town. "It's just a box you check off when visiting the city." Dough infused with butter or olive oil and active dry yeast is left to ferment overnight before it's heaped into a 2-inch-high anodized steel pan to go through several stages of rest. It's pressed along the edges of the pan and covered first with slices of mozzarella to protect the crust from getting soggy, then a layer of toppings like pepperoni or sausage, followed by tomato sauce, before its 40-minute trip through a 500-plus-degree oven. At Labriola, the chefs use three types of tomatoes to make their flavorful sauce imbued with basil, oregano and cayenne.

Basically deep dish with a thin layer of dough across the top and pond of tomato sauce on the top layer, stuffed pizza entered Chicago's pizza atmosphere in 1974. What really sets it apart is the layering: The thick bottom crust gets coated with a layer of cheese, then sauce, then toppings, then a thin layer of crust that encloses the whole Italian-style pie. It's also a bit taller and more packed with ingredients than deep dish. Although stuffed pizza "Is the style of pizza [Chicagoans] typically get mocked for," says Dolinsky, some solid examples can be found throughout the city. The pizza expert praises Suparossa as serving the best in the city, chock-full of gooey cheese and marinara sauce.

While Chicago may be most famous for deep dish, the most-popular pies in town are tavern-style like the ones served at Pat's. Born in bars back in the 1930s, says Dolinsky, this Windy City favorite is a variation of the Midwestern bar pie, somewhat similar to St. Louis' namesake paper-thin pizza but without the Provel. Thinner than even the slimmest New York City slices, these rounds have a cracker-thin crust that is usually topped with tomato sauce, cheese and fennel-heavy Italian sausage that's pinched and pressed onto the pizza right up to the edge. It's sliced up into shareable party squares.

About two and a half hours due west of Chicago, the Quad Cities are made up of four towns that straddle the Mississippi River: Rock Island and Moline in Illinois, and Davenport and Bettendorf in Iowa. That's where you'll find their namesake pies. The dough is infused with brewer's malt, which gives its crisp crust a nutty and sweet taste. It's coated with a dollop of spicy tomato sauce, fennel- and spice-heavy lean pork sausage and a blanket of mozzarella cheese. At family-owned Harris Pizza, that malty crust is also infused with molasses before it's stretched out onto a cornmeal-dusted baking peel, coated with about a pound of sausage (no exaggeration) and a healthy dose of mozzarella and slid into the 500-degree oven. As is customary in the area, the rounds are cut into strips using large scissors.

St. Louis-style pizza gets a lot of flack for its paper-thin crust and its signature cheese. Why all the guff? The unleavened crust is so thin it's almost like a cracker, and the cheese, called Provel, is a processed blend of cheddar, Swiss and provolone. And it's delightful. That gooey, almost buttery cheese product spreads across the crisp base like a nice warm hug. Those Provel-topped rounds, which are often cut into party squares, can be found all over the Gateway to the West, but the place (or places) to try it is Imo's Pizza. Said to be the originator of the Missouri specialty, the local chain is never far from any point in St. Louis: There are more than 90 locations around the city and its surrounding neighborhoods.

Ask small-town Midwesterners the best place to get a pie and one name is sure to come up repeatedly: Casey's General Store. Headquartered in Des Moines, Iowa, the chain of 2,000 gas stations — yes, you read that right — has locations spanning from Ohio to North Dakota, all of which serve its famous pizzas. These thin-crust rounds are made on the premises from scratch-made dough, mild tomato sauce and real mozzarella cheese. Options start with basics like cheese or sausage and move on to more inventive flavor combinations like taco pizza (pictured above), covered with chips, salsa, ground beef and beans. There's even a breakfast variety for those early morning pizza cravings, piled with scrambled eggs, mozzarella and cheddar, and your pick of breakfast meat.

Popular at Pizza Hut, in certain Chicago joints (Pequod's is one) and throughout the Southeast, pan pizza is exactly what it sounds like: The dough is proofed and cooked in a pan, usually with oil or butter, a style of cooking that tends to create a thick, buttery crust. That's what you'll find at Tulsa, Oklahoma, favorite Hideaway Pizza. The 60-plus-year-old place cooks its dough in a beveled cast-iron pan, creating a thick but still crisp crust that has an ardent fan base throughout Oklahoma and in nearby Arkansas. The specialty pies come covered with Hideaway's signature red sauce, different cheese mixtures (mozzarella and cheddar are often combined) and bold topping combinations.

In Omaha, Nebraska, pizza comes with a rich and flaky crust that's more like a biscuit than those crisp rounds found in New York or Chicago. Sure, the city now hosts other pizza styles, such as deep dish and Neapolitan, but its original, namesake style is a buttery rectangle with just a bit of thin tomato sauce and lots of meat. That's the premise of La Casa Pizzeria. Since 1953, the place has been topping its flaky unyeasted dough with unsweet housemade tomato sauce and either mozzarella or piquant Romano cheese (or possibly both). The bottom of each pizza is grilled in a special gas-heated rotating deck oven to give it that special "bakery-style" crust. The go-to topping combination is a blanket of ground beef dotted with onions and mushrooms.

Birthed in 1973 in the gold-mining town of Idaho Springs, the Colorado Mountain Pie offers a Rocky Mountain interpretation of pizza. One local chain, Beau Jo's, has spread the creation through the peaks of the Centennial State. Its pie is chewy, bready and deeper than Chicago's tallest pies, with three different options for the hand-rolled crust — white, honey-whole wheat and gluten-free — sold in 1-, 2- or 3-pound rounds. Each one comes with a generous blanket of cheese (take your pick of 10 kinds), one of 11 different sauce options and your choice of 36 toppings that start with regular pepperoni and turkey pepperoni, then move on to items like Hatch green chiles and broccoli.

California-style pies typically feature a thin, hand-tossed crust covered with unique toppings and bold flavor combinations that represent the Golden State's bounty of produce and its diverse inhabitants. Those innovative toppings can range from barbecue chicken and Thai chicken to avocado carpaccio and mixtures like pear, walnut and blue cheese, and are now found throughout the country at chains like California Pizza Kitchen and independent gourmet pizzerias. It all started at Wolfgang Puck's Spago in Los Angeles when Chef Ed LaDou put a house-cured smoked salmon, red onion and dill creme fraiche pie on the menu in 1982. That rendition is still offered, now with the optional addition of caviar.

Pizza al taglio, Italian for "pizza by the cut," was born in Rome during the 1960s. Pizzeria staff cut hunks of the light and airy rectangles with special scissors according to the size the guests say they want. Takeaway shops in the Eternal City display thick slabs of meter-long cold-fermented dough (hence its other name, "pizza al metro") coated with vibrant toppings ranging from the classic margherita (tomatoes, mozzarella and basil) to artichokes, asparagus and prosciutto. The style has been spreading across the United States in recent years to places like Bonci in Chicago, Rione in Philadelphia and Rock Pizza Scissors in New York. It's all good, but chef-restaurateur Nancy Silverton brings some James Beard Award cred to the style at Triple Beam in Los Angeles. Her options include pepperoni, delicata squash with honey, and chicken sausage, kale and walnut pesto.

Part pizza, part calzone, the Vesuvio is a Neapolitan take on a stuffed pizza. Named after the famous volcano, the pie features two layers of thinly stretched dough, topped with ingredients like cheese, tomatoes and whatever else, and covered with another layer of dough that's stretched out extra thin. Those two rounds are pinched together, and the whole thing is pushed into a wood-fired oven. At Prova in West Hollywood, Chef Vito Iacopelli uses his family's 100-year-old natural-fermentation dough recipe to make his signature Volcano Vesuvio. Stuffed with ricotta, mozzarella, salami di Napoli and San Marzano tomatoes, the "bombe" is cooked in a brick-lined oven until it rises into a peak. The chef then pokes a hole into the top to let the steam erupt.