U.S. Route 412 (abbreviated US-412) is a U.S. highway in the south-central portion of the United States, connecting Springer, New Mexico to Columbia, Tennessee.

In addition to the freeway-grade turnpikes, a large amount of the highway has been upgraded to four-lane expressway facilities, although some portions remain two-lane, especially in the Panhandle.

This extension, in which the new designation replaced or overlapped several already existing highways, brought US-412's western terminus to Woodward.

The three highways enter the state just north of the extreme southwest corner of Cimarron County, the westernmost tip of the Oklahoma Panhandle.

The highways head northeast, passing through disconnected parcels of the Rita Blanca National Grassland.

[2] In Boise City, the highways reach a traffic circle which surrounds the Cimarron County Courthouse.

East of the highway junction, US-412/SH-3 enter Optima National Wildlife Refuge, where they cross Coldwater Creek, one of the lake's tributaries.

At the unincorporated location of Bryan's Corner, approximately 7 miles (11 km) east of the county line, the highway intersects US-83.

While SH-23 passes through the intersection north to south, eastbound US-270, following southbound SH-23 from Beaver, joins US-412/SH-3 heading east.

The three highways continue on, passing through Slapout, before curving slightly to the north as they exit both Beaver County and the Oklahoma Panhandle.

[5][7] On the west edge of town, the four highways serve as the eastern terminus of the western segment of SH-15, a route made discontinuous by the establishment of US-412 (see history).

In downtown, they meet with SH-34; here, US-412 leaves the four-way concurrency, as it continues east by itself while the other three highways it has followed since Fort Supply turn south to overlap SH-34 instead.

For the first time since its western terminus in New Mexico, where it began concurrent with US-56, US-412 is the sole highway designation on the road it follows.

[3] The highway passes just south of Curtis as it continues east out of Woodward County.

[8] In downtown Enid, the routes intersect US-81; US-60 breaks away from US-412 to turn north along US-81, while US-412 continues east along Garriott Road.

The Lone Chimney service plaza, a twenty-four-hour concession area, is located in the median of the turnpike east of the interchange with the spur.

[10] Just south of the county line, the freeway has an interchange with SH-151, a short connector route that runs across Lake Keystone's dam.

[11] The Sand Springs Expressway comes to an end at the northwest corner of the Inner Disperal Loop (IDL), a ring of freeways surrounding Downtown Tulsa.

[12] In Rogers County, the three highways enter the city of Catoosa, one of Tulsa's eastern suburbs.

I-44 and US-412 continue east for a short distance before going separate directions; I-44 exits from US-412 and joins the Will Rogers Turnpike.

US-412 becomes an expressway, and continues east of the interchange, passing through Fair Oaks on its way out of the Tulsa metro.

[2] US-412 continues east through unincorporated territory before reaching Inola, where it has an interchange with SH-88, 1.39 miles (2.24 km) north of that highway's southern terminus.

The turnpike continues east, passing into Delaware County, to intersect US-412 Alternate again between Rose and Leach.

There, US-59 splits away from US-412, while US-412 remains on an easterly trajectory, crossing the state line into Siloam Springs, Arkansas.

Mr. Murphy, deputy director of ODOT, recommended to the Transportation Commission that US-412 be extended into Oklahoma on February 1, 1988.

ODOT hoped that establishing US-412 in Oklahoma would generate new recreational traffic, thus benefiting the state economically.

The new western terminus was to become the US-183/US-270 junction in Woodward; from there, the highway extended for 288.42 miles (464.17 km) to the east, exiting the state in West Siloam Springs.

[18] On May 20, 2021, Senator Jim Inhofe, Republican of Oklahoma, introduced legislation to designate the portion of US-412 between I-35 in Noble County and I-49 in Springdale, Arkansas as future Interstate 42.

The senators' stated reasons for seeking an Interstate designation along the US-412 included encouraging economic development, expanding opportunities for employment in the region, making travel safer and shipping easier, attracting new businesses, and better connecting rural and urban communities.

Other supporters of the measure include the mayor of Tulsa, G. T. Bynum, and the heads of both ODOT and the Arkansas Department of Transportation (ArDOT).