There are 2 US Post Offices in Lyon County serving a total of 7,907 residents equating to 3,954 residents per post office. It's estimated that approximately 12,620 packages are handled across the 2 county post offices annually. Lyon County is a county located in the U.S. state of Kentucky. As of the 2010 census, the population was 8,314. Its county seat is Eddyville. The county was formed from Caldwell County, Kentucky in 1854 and named for former Congressman Chittenden Lyon. It is a limited dry county, meaning that the sale of alcohol is prohibited except by the drink in restaurants in the city of Kuttawa that seat at least 100 diners and derive at least 70% of total sales from food."