Five miles (8.0 km) north of this intersection, US-377/SH-99 serves as the northern terminus for SH-99C, a child route of SH-99.

[5] The highway crosses the Canadian River into Seminole County north of Byng.

The route does not encounter another highway for 19 miles (31 km), after which lies the town of Stroud, the northern terminus of US-377.

[6] Another map published by ODOT of Stroud implies that the route extends north of the ramps to and from I-44 to at least the bridge over the turnpike.

[2] This highway connected Ada to Holdenville; it roughly followed present-day SH-99 until about two miles (3.2 km) north of the Canadian River, it then turned east and passed a mile (1.6 km) south of the unincorporated town of Vamoosa, after which it followed the route of today's SH-56.

After 10 miles (16 km), it passed through Sasakwa, in which it turned north and ended at the original SH-3, at the intersection called "Five-Mile Corner", west of Holdenville.

[14] At its southern end, it was extended along a new alignment, which began at SH-19, present day SH-3, southeast of Ada and ran through Tishomingo and Madill to end at the Red River northwest of Denison, Texas, where it met Texas State Highway 91.

Also that year, a second section of SH-48 was established, taking over a large portion of what was then SH-25; the remainder of the route was integrated into US-60.

[14] On March 1, 1932, a new section of road was designated as State Highway 48, connecting Stroud to SH-33 west of Drumright.

[2] As a result, the SH-48 designation was able to follow existing roads to link up with its previously-disconnected northern section.

[15] On May 17, 1938, both Kansas and Oklahoma renumbered K-11 and OK-48 respectively to bear the number 99, providing continuity between the states.

[1] At this time, SH-99 followed the same basic corridor of the present-day route from Madill north to Kansas.

After SH-48 was discontinued, however, it would only remain discussed for just under three years, SH-48 resurfacing for a route only 13 miles (21 km) east of SH-99.

[18] The existing route of SH-99 (concurrent with SH-3) veered west by about 4 miles (6.4 km) to once again serve the town of Konawa before cutting back northeast to continue the highway's previous heading.

[5][19] This was remedied on December 9, 1968, when the highway was changed to a straighter alignment bypassing Konawa.

On June 18, 1964, the American Association of State Highway Officials (AASHO, later the American Association of State Highway and Transpiration Officiations, AASHTO) accepted an extension of US-377 from Texas to US-70 in Madill.