Bayport is a city in Washington County, Minnesota, United States. The population was 4,024 at the 2020 census. Bayport is located along th…Bayport is a city in Washington County, Minnesota, United States. The population was 4,024 at the 2020 census. Bayport is located along the St. Croix River, one mile south of Stillwater. The City of Bayport began as three small settlements along the St. Croix River. In 1873, the St. Croix Railway Improvement Company combined the three settlements into South Stillwater, which was incorporated as a village in 1881. Because many people confused South Stillwater with the city of Stillwater, the city changed its name to Bayport in 1922.