Union County is a county in the U.S. state of Kentucky. As of the 2020 census, the population was 13,668. Its county seat is Morganfield. The county was created effective January 15, 1811.

Morganfield is a home rule-class city in Union County, Kentucky, in the United States. It is the seat of its county. The population was 3,285 as of the year 2010 U.S. census.