What type of guns do American police officers carry?

In the U.S., different police departments use different guns. As far as handguns go, Glock has 60% or so of the market. Sig has a pretty good percentage of the rest, and there are a few others that have the remainder. In some small cities, individual officers can carry anything they want, but in many large cities, the department usually has a specific model that officers are required to carry.