Why is the urban crime rate higher than the rural?

Crime rates vary greatly across the states. Crime statistics for 2004 seem to dispel the notion that crime is lower in rural states than in urban states, as many of both America's most urbanized and populous as well as rural and scarcely populated states fell well below the national average, while some rural southern states ranked significantly above the national average. Overall, New England had by far the lowest crime rates, for both violent and property crimes. New England states also had the lowest homicide rates in the country. There were so few homicides in New England, in fact, that its homicide rate is lower than that of some western European countries such as Germany and quite similar to that of Canada or the Netherlands. New England is the only region in the United States with a homicide rate so low that it is similar to most other industrialized countries. Other densely populated mid-Atlantic states such as New York and New Jersey also had crime rates well below the national average. Southern states had the highest overall crime rates. The crime rate of Louisiana was more than twice that of Maine, and even the rural state of Arkansas had a crime rate 70.9% higher than that of highly urbanized New York state.