Preheat the oven to 350 degrees F.
Arrange the bacon on a sheet pan and bake for 12 to15 minutes until crisp. Cool and chop.
Put potatoes in a medium sauce pot and cover with cold water. Bring the water to a boil and season with salt. Cook until tender, about 15 minutes. Drain and mash potatoes with buttermilk and season with salt and pepper. Stir in the chives, Cheddar and fold in bacon.