U.S. Route 377 in Oklahoma

State Highway 99
Route information
Maintained by ODOT
Length:	241.5 mi (388.7 km)
Existed:	(as SH-48) January 19, 1927–May 16, 1938 (as SH-99) May 17, 1938 – present
Major junctions
South end:	US 377 at the Texas state line
North end:	K-99 at the Kansas state line
Highway system
Oklahoma State Highway System Interstate U.S. State Turnpikes ← SH-98 SH-100 → ← SH-325 US-377 US-385 →

State Highway 99, abbreviated SH-99, is a north–south state highway through central Oklahoma. It runs from the Texas border at Lake Texoma to the Kansas border near Lake Hulah. It is 241.5 miles (388.7 km) long. The highway overlaps US-377 for over half its length.

SH-99 links up with K-99 after crossing the border into Kansas. This road continues for 233 miles (375 km) to the Nebraska border, where it becomes Nebraska Highway 99, which lasts an additional 14 miles (23 km). Thus, SH-99 is part of a triple-state highway numbered "99", which lasts a total of 488 miles (785 km).

State Highway 99 began as State Highway 48, a short highway connecting Ada to Holdenville. This highway was gradually expanded until it became a border-to-border route. In 1938, it was renumbered to match K-99, which was renumbered from K-11 the same day.

US-377 crosses Lake Texoma on a bridge from Grayson County, Texas into Marshall County, Oklahoma. This is the southern terminus of SH-99, which will concur with US-377 all the way to the U.S. highway's northern terminus in Stroud, a distance of 139.91 miles (225.16 km). The highways' first junction in Oklahoma is with State Highway 32 7 miles (11 km) south of Madill. Five miles north of this intersection, US-377/SH-99 serve as the northern terminus for SH-99C, a child route of SH-99. The routes then head into Madill, where they form a brief concurrency with US-70 and SH-199. US-377/SH-99 head northeast out of town and enter Johnston County.

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Wikipedia