There are 9 US Post Offices in Lafayette County serving a total of 16,094 residents equating to 1,788 residents per post office. It's estimated that approximately 25,688 packages are handled across the 9 county post offices annually. Lafayette County, sometimes spelled La Fayette County, is a county located in the U.S. state of Wisconsin. It was part of the Wisconsin Territory at the time of its founding. As of the 2010 census, the population was 16,836. Its county seat is Darlington. The county was named in honor of the Marquis de Lafayette, the French general who rendered assistance to the Continental Army in the American Revolutionary War."