State Route 126 (SR-126) is a highway completely within the Ogden-Clearfield metropolitan area in northern Utah that makes a loop around Interstate 15 in its more than twenty-one mile path.

It continues this direction through Sunset, Roy, and West Haven before veering to the northwest when the highway reaches Marriott-Slaterville.

Just before terminating in South Willard, the route turns northeast one final time.

The portion of what is now numbered SR-126 from the southern terminus to the junction with SR-26 was previously part of US-91.

[4] The only change from then to now was a portion of the old highway that was relinquished to be used by the city of Layton for parking lots in 1991.