Downtown Salt Lake City is the oldest district in Salt Lake City, Utah. The grid from which the entire city is laid out originates at Temple Square, the location of the Salt Lake City Temple.
Downtown Salt Lake City is usually defined as the area approximately between North Temple and 900 South Streets north to south and about 500 East and 600 West Streets east to west. Downtown encompasses the areas of Temple Square, the Gateway District, Main Street, the core business district, South Temple, and others.
Much of downtown Salt Lake City's early history is intertwined with that of Salt Lake itself at the time. Downtown began to form when Brigham Young chose the spot where the temple of The Church of Jesus Christ of Latter-day Saints was to be located.
Originally, due to the Mormon faith's tendency towards socialism in its early years, no provision was made for a business district. Over the years, the city's core took shape as businesses located themselves around Main Street. The first businesses to locate themselves on Main Street were those founded by James A. Livingston and Charles A. Kincade in 1850 in the area south of the Council House that was being built on the corner of Main and South Temple Streets.
Early on, many of the Main Street businesses were saloons, earning the street the nickname "Whiskey Street".
The city, as well as the county, is laid out on a grid plan; Most major streets run very nearly north-south and east-west. There is about a fourteen to fifteen minute of arc variation of the grid from true north. Its origin is the southeast corner of Temple Square, the block containing the Salt Lake Temple of The Church of Jesus Christ of Latter-day Saints. Addresses are coordinates within the system. This is similar to latitude and longitude. One hundred units are equal to 1/8th of a mile, the length of blocks in downtown Salt Lake City. The streets are relatively wide, a version of the original settlers, who wanted them wide enough that a wagon team could turn around.
The original city plan was to be developed into 135 10-acre lots. However in the 19th century and before the zoning ordinances of the 1920s the blocks became irregular. The original 10-acre blocks allowed for large garden plots, and were supplied with irrigation water from ditches that ran approximately where modern cur and gutter is laid. The original water supply was from City Creek. Subsequent development of water resources was from successively more southern streams flowing from the mountains to the east of the city. Some of these irrigation ditches are still visible in the eastern suburbs.
There are three distinct street patterns in Salt Lake City, the first of which are the initial square blocks crisscrossed by later small streets. The second district pattern are the 2.5 acre blocks in the Avenues. The final section is the rectangular blocks south from 900 South.