As per the original issue of Rural vs. Urban salaries, I'd like to point out this; You can really see the difference with PD departments, because I believe that just about every City and town in the U.S. has one. And, we also have county, state, and Federal Law enforcement, but since we haven't gone into those areas yet, so Municipal PD's it is...You see a big difference in salaries' mainly because, well, you have a massive cost of living difference between those areas, as well as a factor for more 'severe' duty. (Think the difference between South-central L.A. and a 2,000-4,000 population town in Iowa, for example.) In L.A., for instance, Rent's there can start at 1500$ a month for a one-bedroom apartment, for example, and what does that get you in Iowa? A dollar goes' farther in rural areas, and it has for a long time.
Hey, the salary difference goes across just about all occupations. Union scale wage for most of the people in my trade (Construction equipment operation) is close to 37$ an hour. But, you go to other states', like Washington, Colorado, Arizona, etc. It drops' to about 17-20$. And it does that for a lot of trades. You might make more in the big city, but you're gonna have to spend more, as well.