US-77 enters the state along with I-35 but splits off at the first exit in Oklahoma. Four miles later, it passes through
Thackerville. It junctions with
State Highway 32 on the west side of
Marietta. North of Marietta, US-77 passes to the west of Lake Murray and its state park. It then enters
Carter County and Ardmore, where it is named Commerce Street through the city limits over a four-lane divided thoroughfare that includes frontage roads on each side from just south of
SH-199 (West Broadway) to NW 12th Street much like a freeway or expressway, though all intersections on Commerce are at-grade. North of Ardmore, US-77 continues as a four-lane divided highway to Springer. It crosses
State Highway 53 south of
Springer. North of Springer, US-77 reverts to a two-lane highway and enters the
Arbuckle Mountains, providing access to
Turner Falls and having some hairpin curves over a section of roadway paved and constructed in the 1920s using prison labor from the Oklahoma State Penitentiary in McAlester. It then passes through
Davis (where it has a brief
concurrency with
State Highway 7. North of Davis, it passes through unincorporated
Joy and passes through
Wynnewood, where it carries
State Highway 29. It then passes through
Pauls Valley,
Paoli, and
Wayne. Next, it enters
Purcell, where it concurs with
State Highway 39 and
74. US-77 and SH-39 split off SH-74 to head eastbound along Washington St. in downtown Purcell. Together, they cross the
James C. Nance Memorial Bridge into
Lexington, where SH-39 splits off. It then heads through
Slaughterville and
Noble before entering
Norman. A major reconstruction on US-77 through
Norman completed in April 2009 has realigned US-77 to 12th Avenue East from SH-9 to Tecumseh Road, then west along Tecumseh Road to Flood Avenue, and finally north along Flood Avenue until it merges onto Northbound Interstate-35, the interchange of US-77 and Interstate-35 was modernized and upgraded as part of the widening to six lanes of Interstate-35 to Norman. It formerly ran through downtown Norman along Classen Boulevard, Porter Avenue then west along Robinson Street to Flood Avenue. The north–south section of the new alignment along 12th Avenue was previously flagged as SH-77H. I-35 and US-77 remain together until the
Fort Smith Junction in downtown Oklahoma City, where it transfers onto
Interstate 235. At
Interstate 44, I-235 ends, but US-77 continues northbound as a freeway, called the Broadway Extension. The Broadway Extension is a major freeway linking the downtown area to
Edmond. In Edmond, it heads east to meet I-35, which it joins again until Guthrie, where it splits off. In Guthrie, US-77 meets
State Highway 33. It continues northbound to serve as the eastern terminus of
State Highway 164 and turns eastward toward
Perry. After passing the north end of
State Highway 86, it turns back northward and has a half-interchange with the
Cimarron Turnpike. It then carries
State Highway 15 for . At
Tonkawa, it begins a
wrong-way concurrency with
U.S. Highway 177 and
U.S. Highway 60. It splits off to the north to head through Ponca City and
Newkirk, before crossing over the Kansas line towards
Arkansas City, Kansas. ==History==