West of the Oklahoma City area, it has been largely replaced by I-40; the few independent portions that are still state-maintained are now I-40 Business.

However, from Oklahoma City northeast to Kansas, the bypassing I-44 is mostly a toll road, and SH-66 remains as a free alternate.

Route 66 was eliminated by the American Association of State Highway and Transportation Officials on April 1, 1985.

The bridge over the North Fork of the Red River in Sayre was built of timber in 1924 and upgraded and widened with steel in 1933.

Beyond Erick, the PC was again built in the present location of the westbound lanes, but has since been paved over until the I-40 interchange (exit 11).

Just past exit 11, the road becomes two lanes, and the original road — mostly built as PC, but later resurfaced in asphalt, and once the westbound lanes of a divided highway - is now abandoned to the north of the open roadway; a 1928 concrete federal aid primary marker lies 0.8 miles (1.3 km) west of Hext.

However, it continued beyond Benton Boulevard to Sayre Avenue, turning off onto the present four-lane I-40 Bus.

Between exit 32 and Elk City, the original road (resurfaced) is now the westbound lanes of I-40 Bus., where another 1926 box drain still stands.

When Route 66 was decommissioned on April 1, 1985, the Sayre and Elk City business loops were created.

The continuation of the Northeast Expressway to the Oklahoma City Terminus of the turnpike was labeled SH-66A; this route had extended west to May Avenue before March 2.

[10] A relocation, approved on July 7, 1932, simplified the routing through Tulsa, taking it east on 11th Street all the way from the bridge to 193rd Avenue.

)[1][16] US 66 Bypass was established on June 4, 1951, along the proposed Skelly Drive, which was not finished until the late 1950s, when it became part of I-44.

(The only change in this route was made in the early 1970s,[17] during construction of I-444, when it was moved to 12th Street west of Denver Avenue.)

One may either continue on SH-66 all the way through town, or divert one block west and take the older alignment down J.M Davis Blvd.

In Chelsea, SH-28 briefly merges with SH-66, then diverges north after about 5 blocks, while SH-66 continues toward White Oak.

Fort Reno served as a US military post from 1874 (long before Oklahoma attained statehood) through World War II.

[20] The Chandler Armory, built under the Works Progress Administration during the Great Depression, served as home of the 45th Infantry Division of the Oklahoma National Guard during World War II and continued in service until replaced by a modern building in 1971.

The restored native folk art collection of Ed Galloway's Totem Pole Park in Foyil dates from 1937.

[23] Tulsa landmarks include the giant Meadow Gold neon sign at 11th & Peoria.

[31] The 1939 sandstone Rock Café[32] contains a large collection of both local memorabilia and souvenirs from Pixar's research of US 66 in the area for the animated film Cars.

Proprietor Dawn Welch is the model on which Sally Carrera, the Radiator Springs hotelier who fights to rebuild and restore the town, is based.

The Oklahoma Route 66 Museum in Clinton was built on land donated by the late Walter S. Mason Jr., a retired country veterinarian who once served as president of the Best Western hotel chain.

[45] Tulsa, Oklahoma, has The Cyrus Avery Centennial Plaza, located next to the east entrance of the historic 11th Street Bridge.

[46] The Plaza contains a giant sculpture weighing 20,000 pounds (9,100 kg) and costing $1.178 million[47] called "East Meets West" of the Avery family riding west in a Model T Ford meeting an eastbound horse-drawn carriage.

[48] In 2020, Avery Plaza Southwest opened at the west end of the bridge, which features a “neon park” with replicas of the neon signs from Tulsa-area Route 66 motels of the era, including the Tulsa Auto Court, the Oil Capital Motel, and the famous bucking-bronco sign of the Will Rogers Motor Court.

is the Route 66 Historical Village, which includes a tourism information center modeled after a 1920s-1930s gas station, and other period-appropriate artifacts such as the Frisco 4500 steam locomotive with train cars.

[55] Just west of Tulsa in Sapulpa is the Heart of Route 66 Auto Museum which opened in August 2016 in an Armory built in 1948.

It features the world's tallest replica of an antique visible gas pump, being 66 feet in height.