Nauvoo, Illinois, a historic community in Hancock County. It is located on the Mississippi River, 45 miles (72 km) north of Quincy. Nauvoo was once the largest city in the state. It served as headquarters for the Mormon church, 1839-46, and is the site of a restoration project begun in 1962 by the Church of Jesus Christ of Latter-day Saints. Many buildings have been reconstructed, including the Brigham Young House. Also in Nauvoo are the mansion and gravesite of Mormon founder Joseph Smith, which are preserved by the Reorganized Church of Jesus Christ of Latter Day Saints.
Nauvoo was founded as Quashquema by Sac and Fox Indians. The Mormons arrived in 1839, having been expelled from Missouri, Nauvoo soon had more than 20,000 residents. However, anti-Mormon sentiment had developed in Illinois. In 1844 Joseph Smith and his brother Hyrum were murdered; in 1846 the Mormons abandoned the city. A group of French immigrants, known as the Icarians, made an unsuccessful attempt to establish a communistic colony here in 1850. Thereafter, Nauvoo declined in importance.