Lincoln County is located in the eastern part of the U.S. state of Missouri. As of the 2020 census, the population was 59,574. Its county seat is Troy. The county was founded December 14, 1818, and named for Major General Benjamin Lincoln of the American Revolutionary War.

Troy is a city in Lincoln County, Missouri, United States. As of 2019, the estimated population was 12,820. It is the county seat of Lincoln County. Troy is an exurb of St. Louis, and is part of the St. Louis Metropolitan Statistical Area.