Daniel Spencer (1794-1868) served as a member of the Nauvoo City Council and as mayor of Nauvoo. Daniel served missions to Canada, Massachusetts, and to the American Indians. He was instrumental in helping the Mormon Pioneers cross the plains and his was the first group to enter the Salt Lake Valley after Brigham Young.

Daniel Spencer Jr. was born the son of Daniel and Chloe Spencer in West Stockbridge, Massachusetts on July 20, 1794. He was the fourth child of eleven children in the Spencer family, and the third son in the family. During his early years he was a merchant, a peddler, a member of the local school board, and an investor in local real estate. In 1840, he joined the Church of Jesus Christ of Latter-day Saints and became the branch president of the Union Branch of West Stockbridge and Richmond in western Massachusetts. He was instrumental in the conversion of a number of individuals including his younger brothers Hiram and Orson and their families. Orson and his family moved to Nauvoo, Illinois in 1841, and Daniel and Hiram and their families moved to Nauvoo in 1842. Daniel served missions to Canada, to the Kansas territory and American Indians, to Massachusetts, and to England. He was a member of the Nauvoo City Council and for six months following the death of Joseph Smith, he served as the Mayor of Nauvoo. His brother Orson also served on the Nauvoo City Council. He was among those initially selected by Joseph Smith to be a member of the exploring expedition to the Rocky Mountains in 1844, but this mission never took place because of the death of Joseph Smith in June 1844. Daniel was a member of the Council of Fifty. In 1845, with Amasa Lyman, he was sent to the James Emmett group in north-western Iowa to convince them to return to Nauvoo.

Daniel was appointed by Brigham Young as a Captain of 50 in the Mormon Exodus from Nauvoo from February to June 1846. This diary is an account of part of that trek from Nauvoo to Winter Quarters. He was called as a Bishop in Winter Quarters. In 1847, he was appointed a Captain of two companies of 50, and his group was the first pioneering company to enter the Salt Lake Valley following the arrival of the earlier group led by Brigham Young. From 1849-1868 he served as the President of the Salt Lake Stake except from 1852-1856 when he served a mission to England. He was a member of the Utah Territorial Legislature and while in the capacity of Stake President served as a municipal judge in Salt Lake Valley. During his lifetime, Daniel was the husband of nine wives and left a posterity of 27 children. He died in Salt Lake City on December 8, 1868.