Lewiston is a city in Winona County, Minnesota, United States. The population was 1,620 at the 2010 census. A post office called Lewist…Lewiston is a city in Winona County, Minnesota, United States. The population was 1,620 at the 2010 census. A post office called Lewiston has been in operation since 1872. The city was named for Jonathan Smith Lewis, a pioneer settler. Lewiston was incorporated in 1873. Lewiston - the first stop on the Winona-Rochester stagecoach line - was an important source of support for those travelers.