La Paz is one of the 15 counties in the state of Arizona. It was created in 1983 from part of Yuma county, making it the Arizona's newest. As of the 2010 census, the population was 20,489. The county seat is Parker. This county is the first and only county in Arizona to be created after its statehood in 1912. At first, this county required federal money from neighboring Yuma County, and as a result, the legistature passed laws making splitting existing counties much more difficult.