Fall River County
There are 4 US Post Offices in Fall River County serving a total of 7,716 residents equating to 1,929 residents per post office. It's estimated that approximately 12,316 packages are handled across the 4 county post offices annually. Fall River County is a county located in the U.S. state of South Dakota. As of the 2010 census, the population was 7,094. Its county seat is Hot Springs. The county was founded in 1883. It is named for Fall River which runs through it."