From this point, it heads northwest, serving as the southern terminus of State Highway 1 and the main street of Mannsville.

US-177 then runs through the Chickasaw National Recreation Area and the town of Sulphur, where it has a brief concurrency with SH-7.

US-177 continues north into western Garvin County, serving as the eastern terminus of SH-29 and crossing SH-19 in Stratford.

The three highways then cross the Canadian River into Pottawatomie County, where they meet SH-39 at a four-way stop in Asher.

Just west of Warwick, it meets SH-66 (old Route 66), and then passes under Interstate 44 (the Turner Turnpike), with no interchange.

US-177 then continues north, connecting to the town of Carney via SH-40A, the shortest state highway in Oklahoma.

It then passes through the county seat, Stillwater, the home of Oklahoma State University.

Farther north, in Noble County, it crosses US-64 and the mainline of the Cimarron Turnpike.

It serves Ponca City, where it begins a wrong-way concurrency with its parent, US-77, as well as US-60 (which is signed the "correct" direction).

Only 4 mi (6.4 km) north of the state line, US-177 ends at US-81 in downtown South Haven, Kansas.