How Salt Lake City's address grid works

The whole Salt Lake Valley is one big coordinate system. Once you can read it, you can place almost any photo, which is the entire trick to Salt Lake Gridy.

Everything counts from Temple Square

The grid starts at the southeast corner of Temple Square, where Main Street meets South Temple. That corner is zero in every direction. Main Street is the 0 East/West line and South Temple is the 0 North/South line, and the numbered streets count outward in hundreds: State Street is 100 East, West Temple is 100 West, North Temple is 100 North, and so on down the valley to 14600 South.

Every 100 is one nominal block. So 900 East is nine blocks east of Main Street, and 2100 South is twenty-one blocks south of South Temple.

Reading an address like 1300 E 2100 S

A pair like 1300 E 2100 S is a coordinate: 13 blocks east and 21 blocks south of Temple Square. That is the heart of Sugar House. A few more to get your bearings:

Real house numbers follow the same logic. A building at 455 East 2100 South sits on 2100 South, a little over halfway between 400 East and 500 East. Numbers are assigned proportionally between the grid streets, so the address itself is a pretty exact location.

City blocks and county blocks are not the same size

The original Salt Lake City plat of 1847 used ten-acre blocks: 660 feet square with 132-foot-wide streets. That makes each 100 address units about 792 feet, so a mile is only about 670 units, roughly seven blocks. The county grid laid out later, south and west of the city, used a cleaner rule: 800 units to the mile, eight blocks, each 660 feet from centerline to centerline.

That is why the big east-west arterials in the south valley are exactly a mile apart and land on odd-looking numbers: 5400 South, 6200 South, 7000 South, 7800 South, 8600 South, 9400 South. And it is why 4000 West, 4800 West and 5600 West are the mile roads on the west side.

The transition between the two systems is messy. Between roughly 2100 South and 5400 South, and between Redwood Road and 3200 West, the spacing changes street by street. Salt Lake Gridy's map was calibrated from almost 700 surveyed intersections so its grid lines follow the real streets instead of assuming one block size.

Streets that jog

Several numbered streets do not sit on their nominal line for their whole length. 2200 West near the airport is about a quarter mile west of 2200 West in West Jordan. 2700 South, 3500 South, 4700 South and 300 West all shift by a block or more somewhere along their run. Addresses on those streets still use the street's name, so the game follows the street, not the theoretical line.

Using the grid to place a photo

Players who do well at Salt Lake Gridy are not recognizing specific buildings. They are reading the landscape against the grid:

• The mountains tell you east from west. The Wasatch rise on the east side of the valley and the Oquirrhs on the west. If Mount Olympus looms large and close, you are far east; if the Oquirrhs are near, you are out past Bangerter Highway.
• Block size tells you city from county. Short blocks, wide streets, parking strips and old brick bungalows say Salt Lake City proper. Long blocks and cul-de-sacs say the suburbs.
• Street signs give you the number directly. Any legible green sign with a number on it is a gift. Even a partial number narrows things a lot.
• Transit and freeways are landmarks. TRAX runs down Main Street, out 400 South to the university, along North Temple to the airport, and south through Murray, Midvale and Sandy. The I-15 and I-80 corridors, the Jordan River and the Surplus Canal all cut the valley into recognizable pieces.
• Slope and elevation. The east bench climbs steadily toward the Wasatch. If the street is noticeably uphill to the east, you are on the bench, somewhere above 1300 East.

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