See the context of this sign.

Great Salt Lake
Base and Meridian

Latitude 40o 46' 04" - Longitude 111o 54' 00"
Altitude (sidewalk) 4327.27 ft.

Fixed by Orson Pratt assisted by Henry G. Sherwood,
August 3, 1847, when beginning the original survey of
"Great Salt Lake City," around the "Mormon" temple site
designated by Brigham Young July 28, 1847, the city streets
were named and numbered from this point.

David H. Burr, first U.S. Surveryor-General for Utah,
located here in August 1855, the initial point of public
land surveys in Utah, and set the stone monument, still
preserved in position.

An astronomical station, its stone base still standing
100 ft. N, and 50 ft. W. of this corner was established by
George W. Dean, U.S. G.&G. Survey, September 30, 1869, to
determine the true latitude and longitude; it was used to
obtain correct time at this point until December 30, 1897.

Don't miss the rest of our virtual tour of Salt Lake City, Utah in 2477 images.