Oklahoma State Highway 6

SH-6 south of Granite

After crossing the Red River, State Highway 6 leaves Texas, becomes SH-6 and continues headed northeast, passing through the small Jackson County towns of Eldorado and Olustee. Highway 6 meets US-62 five miles (8 km) west of Altus.[2] SH-6 makes a right turn at this point to overlap US-62 into Altus.

In Altus, SH-6 takes a turn to the north to overlap US-283. North of Blair, US-283 heads due north while SH-6 turns toward the northwest. SH-6 crosses US-283 once more before the state highway continues to the north toward Granite, where it meets SH-9.

North of Granite, SH-6 runs along the Beckham–Washita county line until sharing a 4-mile (6.4 km) concurrency with SH-55, moving into Beckham County.[2] After splitting away from SH-55, it meets SH-152 for the first time (it will meet SH-152 at its northern end.)

SH-6 continues north to have an interchange with Interstate 40 in Elk City. It overlaps Business Loop I-40 for four miles (6.4 km) on the north side of the city.[2] At this point the north–south highway curves to the west. It crosses US-283 (again), and then ends at SH-152 in Sweetwater.

SH-6 in downtown Elk City

The original State Highway 6 extended from the Texas state line near Colbert to the Kansas state line north of Vinita.[3] When the United States Numbered Highways system was established in 1926, the vast majority of the highway was overlapped by US-75 and US-73.[4] (Later, this corridor would form the majority of US-69 in Oklahoma). As a result, the original SH-6 designation was decommissioned soon after the establishment of the U.S. highway system.

The SH-6 designation remained unused until August 21, 1954, when it was assigned to a highway beginning at US-283 east of Mangum, extending north through Granite and Retrop, and ending at US-66 in Elk City.[5][6] The highway was extended west along SH-73 to its current northern terminus on January 21, 1957.[5]

SH-6 was extended to the south on July 7, 1975, bringing it to Altus by way of a concurrency with US-283, where it joined US-62 in another concurrency, headed west. West of Altus, the route split off and headed southwest to the Texas state line. In addition to the U.S. routes, SH-6 was concurrent with SH-44 between that route's current southern terminus and Eldorado, where it ended; thereafter, SH-6 followed SH-34 to the Red River. To remove the redundant designations, both SH-34 and SH-44 were truncated to their current southern terminus on January 5, 1987.[5][7][8]

SH-6 was realigned twice in 2004 to allow SH-6 a straighter route in situations where it was concurrent with another highway. The first such section removed a portion of the US-283 concurrency between Blair and Granite; the second realignment took place on the SH-55 concurrency north of Retrop. Both of these changes were applied to the highway on February 2, 2004.[5] No further changes to the highway's route have taken place since then.

• SH-6 at OKHighways