Morristown is a city in Rice County, Minnesota, United States. The population was 949 at the 2020 census. Morristown was platted in 18…Morristown is a city in Rice County, Minnesota, United States. The population was 949 at the 2020 census. Morristown was platted in 1855, and named for Walter Morris, a pioneer settler. According to the United States Census Bureau, the city has a total area of 1.03 square miles ; 1.02 square miles is land and 0.01 square miles is water.