State Route 31 (SR-31) is a state highway in Sanpete and Emery Counties in the U.S. state of Utah. It runs for 47.746 miles (76.840 km) from US-89 at Fairview to SR-10 in Huntington. The highway has been designated as part of The Energy Loop, a National Scenic Byway.

SR-31 begins at an intersection with US-89 at Fairview and runs east northeast for approximately 10 miles (16 km), then turns southeast for the remainder of the route, terminating at an intersection with SR-10 at Huntington.

Just off State Route 31, about 15 miles (24 km) west north-west of Huntington, is Crandall Canyon, location of the Crandall Canyon coal mine. On Monday, August 6, 2007, at 2:48 A.M., the mine collapsed, trapping and killing six workers inside. A second collapse on August 16, 2007, killed a Mine Safety and Health Administration investigator and two more miners, bringing the total to nine.

The road from SR-32 (by 1926 US-89) in Fairview east to the Sanpete-Emery County line, near the present north end of Electric Lake, was added to the state highway system in 1915. It was extended southeast to SR-10 in Huntington in 1918, and in 1927 the state legislature numbered the Fairview-Huntington highway as SR-31. A major realignment was made in 1976, when Electric Lake was created and a new route was built to the west. The old route in Sanpete County became a county road, and is now part of SR-264, but the majority of the road in Emery County was beneath the lake and thus abandoned.

County	Location	mi	km	Destinations	Notes
Sanpete	Fairview	0.000	0.000	US 89 (State Street) – Mount Pleasant, Provo	Western terminus
		0.085	0.137	SR-231 south (State Street) to US 89 south
	​	8.576	13.802	SR-264 (Eccles Canyon Scenic Byway) – Scofield
Emery	Huntington	47.746	76.840	SR-10 (Main Street) – Castle Dale, Price	Eastern terminus
1.000 mi = 1.609 km; 1.000 km = 0.621 mi

• List of state highways in Utah

Media related to Utah State Route 31 at Wikimedia Commons