The Endowment House stood on the northwest corner of Temple Square. Initially, it was a two-story adobe building, 44 feet by 34 feet, with a single-story 20-foot extension on its north side. In 1856 another extension was added on its south side and a baptistry on its west side.
Inside, it was the first building designed specifically for administering temple rituals. Earlier buildings used for such purposes, Joseph Smith’s Red Brick Store in Nauvoo, the Nauvoo Temple and the Council House, only had temporary canvas partitions. It had the typical ordinance rooms found in some later Mormon temples: creation room, garden room, world room, celestial room, as well as a sealing room. In 1856 William Ward painted the walls of the creation room to represented the Garden of Eden, the first such temple mural. It was one of the first buildings in Utah to have indoor bathrooms.
The building was used primarily for performing temple ordinances. From 1857 to 1876 the baptismal font was used to perform 134,053 baptisms for the dead. Between 1855 and 1884 54,170 persons received their washings and anointings and endowments. Between 1855 and 1889 68,767 couples were sealed in marriage—31,052 for the living and 37,715 for the dead.
Mormons did not consider the Endowment House a temple, so they did not perform all temple ordinances in it. Brigham Young explained, “We can, at the present time , go into the Endowment House and be baptized for our dead, receive our washings and anointings, etc....We also have the privilege of sealing women to men without a Temple....but when we come to other sealing ordinances, ordinances pertaining to the holy Priesthood, to connect the chain of the Priesthood from father Adam until now, by sealing children to their parents, being sealed for our forefathers, etc., they cannot be done without a temple” (Journal of Discourses, 16:185). Hence, there were no sealing of children nor endowments for the dead performed in the Endowment House. These ordinances were first administered in Utah’s first temple, the St. George Utah Temple, in 1877.
It was also used for other purposes, including prayer circles, setting apart and instructing missionaries before their departure, as well as meetings of the various church leaders, such as the First Presidency and Quorum of the Twelve Apostles.
The Endowment House became a casualty of the anti-polygamy campaign of the U.S. Federal Government, especially the Edmunds-Tucker Act of 1887, which disincorporated the LDS Church and allowed the federal government to seize all of its assets. In response the Church leaders ceased performing new plural marriages. In October 1889 Wilford Woodruff, President of the Church, learned that a plural marriage had been performed the previous spring in the Endowment House without his permission. After discussing the matter with the Quorum of the Twelve Apostles, he ordered the building razed without delay. The Salt Lake Tribune in its November 17, 1889, issue reported that the building was "being demolished." By the end of the month all trace of the Endowment House was gone. Some two years later Woodruff issued the 1890 Manifesto, officially ending the Mormon practice of polygamy, which had been so firmly associated in the mind of the public with the Endowment House.
Reports have circulated that the Endowment House at Salt Lake City may not have been the only non-temple structured used for administering temple ordinances in Utah. Another possible candidate is the so-called Endowment House in Spring City, Utah, built by Orson Hyde. Local records seem to indicate, however, that this building was a Relief Society hall and was never used to administer temple ordinances.