State Route 56 is a highway completely within Iron County in southwestern Utah going from the Utah/Nevada border to Cedar City.

From its western terminus on the Nevada border near Modena, the route heads northeast until reaching Modena, where it turns southeast. It continues this direction until Newcastle, where it begins heading east and then southeast. After a junction with Pinto Road, it leaves the Harmony Mountains, enters Cedar Valley, then the route heads northeast until entering Cedar City, where it runs east until its eastern terminus.

The road from Beryl Junction west to Modena became a state highway in 1918, and in 1927 the legislature extended it west to the Nevada state line (at SR 25) and numbered it as part of SR-18. A connection from SR-18 at Beryl Junction east to SR-1 (US-91, now SR-130) in Cedar City was added in 1931 as State Route 56, and in 1935 that route absorbed the segment of SR-18 to the state line.

SR-56 originally crossed the mountains between Cedar City and Beryl Junction via Desert Mound, following the present Desert Mound Road. Two branches from SR-56 to Iron Mountain were added in 1935: State Route 120 directly south from about the midpoint (never built[citation needed]), and State Route 198 from near the Cedar City end southwest via Iron Mountain to the Dixie National Forest in the direction of Pinto. Both routes were deleted in 1945, and SR-56 was realigned via Iron Mountain, with the portion of SR-198 east of that settlement becoming part of the new route. A 1953 law restored part of the old alignment to the state highway system as State Route 253, from the junction west of Cedar City to Desert Mound, and also created State Route 254 as a branch to Iron Springs. Both were given back to the county in 1969.