State Route 366 (SR 366) is a highway in

Graham County, Arizona Graham County is a county in the southeastern part of the U.S. state of Arizona. As of the 2020 census, the population was 38,533, making it the third-least populous county in Arizona. The county seat is Safford. Graham County composes the ...

that runs from its junction with

US 191 U.S. Route 191 (US 191) is a spur of U.S. Route 91 that has two branches. The southern branch runs for from Douglas, Arizona on the Mexican border to the southern part of Yellowstone National Park. The northern branch runs for from the north ...

south of Safford to near the summit of

Mount Graham Mount Graham (called in Nnee biyati' (Western Apache) Dził Nchaa Sí'an - ′Big Seated Mountain′) is a mountain in Graham County, Arizona, United States, approximately northeast of Tucson. The mountain reaches in height. It is the highes ...

. It is a winding mountain road with one half primarily a northwest-southeast route, the other half being northeast-southwest.

Route description

SR 366 is a highway that connects

with US 191 (originally US 666) at Swift Trail Junction south of Safford. The western terminus of the highway is located near a ranger station near the peak of Mount Graham. The highway heads in a southeastern route as it descends the mountain. There are several hair pin turns as the highway follows the terrain. At Turkey Flat, the highway goes through a series of five hair pin turns. The highway also begins to generally head in a northeasterly direction from this point on. The terrain eventually smooths out and the highway follows a straight path towards the northeast to its eastern terminus at US 191. SR 366 traverses sparsely inhabited forest and mountain terrain and does not pass through any cities or towns aside from minor settlements. The highway does provide access to Mount Graham, one of the higher peaks in

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

at over . It also provides access to the

Mount Graham International Observatory Mount Graham International Observatory (MGIO) is a division of Steward Observatory, the research arm for the Department of Astronomy at The University of Arizona, in the United States. It is located in southeastern Arizona's Pinaleño Mountains n ...

. Part of SR 366 is designated as the Swift Trail Parkway under the Arizona Parkways, Historic and Scenic Roads program.

History

SR 366 was established in 1960 from a junction with US 666 (now US 191) to the southwest for . Later that same year, it was extended an additional to the Columbine Ranger Station. At this time the road was a gravel road providing access to the Coronado National Forest. Since that time, the easternmost have been paved while the rest remains as a gravel road.

Junction list

References

External links

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Arizona Roads
366 Transportation in Graham County, Arizona