Tracy is a city in Platte County, Missouri within the United States, located along the Platte River. The population was 269 at the 2020 census. T…Tracy is a city in Platte County, Missouri within the United States, located along the Platte River. The population was 269 at the 2020 census. The city is part of the Kansas City metropolitan area. Tracy was laid out in 1872, and named for J. W. Tracey, a superintendent of the Chicago, Rock Island and Pacific Railroad. A post office called Tracy has been in operation since 1882.