Troy is a city in Lincoln County, Missouri, United States. As of the 2010 census the population was 10,540. It is the county seat of Lincoln County.
Troy is part of the St. Louis Metropolitan Statistical Area.
Troy was platted in 1819. Some say the community was named after Troy, New York, while others believe the name is a transfer from Troy, Vermont. An early variant name was Woods Fort. A post office called Troy has been in operation since 1823.
Fort Cap au Gris, a War of 1812 fortification, was built near Troy in 1814. Lincoln County Medical Center was established in Troy in 1953 under the Hill-Burton Memorial Hospitals Act, as Lincoln County Memorial Hospital. Cuivre River State Park, one of the largest of Missouri's state parks, lies approximately three miles to the northeast of Troy, across the Cuivre River valley.