Nauvoo is a small city in Hancock County, Illinois, United States, on the Mississippi River near Fort Madison, Iowa. The population of Nauvoo was 1,149 at the 2010 census. Nauvoo attracts visitors for its historic importance and its religious significance to members of several groups: The Church of Jesus Christ of Latter-day Saints; the Community of Christ, formerly the Reorganized Church of Jesus Christ of Latter Day Saints; other groups stemming from the Latter Day Saint movement; and the Icarians. The city and its immediate surrounding area are listed on the National Register of Historic Places as the Nauvoo Historic District.