Police work is heavily decentralized in America, with a huge number of federal, state, county, city, and town police agencies. According to Wikipedia, based on Bureau of Justice statistics, America has:
17,985 state and local police departments, half of which employ 10 or fewer officers
765,000 full-time and 44,000 part-time commissioned police officers, plus about 315,000 full-time support personnel, employed by state and local agencies, two-thirds of whom work for departments employing 100 or more officers
About 60% of these work for local police departments and 24% work for sheriff’s departments
120,000+ federal officers authorized to carry firearms and make arrests
There is roughly 1 police officer for every 250 U.S. residents
Wow thats a small number