The few remaining Mormons left in Nauvoo, Illinois, formally dedicate the Nauvoo Temple.
Mormons are a religious and cultural group related to Mormonism, the principal branch of the Latter Day Saint movement started by Joseph Smith in upstate New York during the 1820s. After Smith's death in 1844 the movement split into several groups following different leaders; the majority followed Brigham Young, while smaller groups followed Joseph Smith III, Sidney Rigdon, and James Strang. Most of these smaller groups eventually coalesced into the Community of Christ, and the term Mormon typically refers to members of The Church of Jesus Christ of Latter-day Saints (LDS Church), as today this branch is far larger than all the others combined. (Since 2018, the LDS Church has requested that its members be referred to as "Latter-day Saints".) People who identify as Mormons may also be independently religious, secular and non-practicing, or belong to other denominations.
Mormons have developed a strong sense of community that stems from their doctrine and history. One of the central doctrinal issues that defined Mormonism in the 19th century was the practice of plural marriage, a form of religious polygamy. From 1852 until 1904, when the LDS Church banned the practice, many Mormons who had followed Brigham Young to the Utah Territory openly practiced polygamy. Mormons dedicate significant time and resources to serving in their churches. A prominent practice among young and retired members of the LDS Church is to serve a full-time proselytizing mission. Mormons have a health code which eschews alcoholic beverages, tobacco, tea, coffee, and addictive substances. They tend to be very family-oriented and have strong connections across generations and with extended family, reflective of their belief that families can be sealed together beyond death. They also have a strict law of chastity, requiring abstention from sexual relations outside heterosexual marriage and fidelity within marriage, though the Community of Christ is accepting of LGBTQ individuals and relationships.
Mormons self-identify as Christian, but some non-Mormons consider Mormons to be non-Christian because some of their beliefs differ from those of Nicene Christianity. Mormons believe that Christ's church was restored through Joseph Smith and is guided by living prophets and apostles. Mormons believe in the Bible, as well as other books of scripture, such as the Book of Mormon. They have a unique view of cosmology and believe that all people are literal spirit-children of God. Mormons believe that returning to God requires following the example of Jesus Christ, and accepting his atonement through repentance and ordinances such as baptism.
During the 19th century, Mormon converts tended to gather to a central geographic location, a trend that reversed somewhat in the 1920s and 30s. The center of Mormon cultural influence is in Utah, and North America has more Mormons than any other continent, although the majority of Mormons live outside the United States. As of December 2020, the LDS Church reported having 16,663,663 members worldwide.