Oklahoma State Highway 99

State Highway 99
Route information
Maintained by ODOT
Length	241.5 mi[3] (388.7 km)
Existed	May 17, 1938[1]–present
History	Previously SH-48 January 19, 1927 – May 16, 1938[2]
Major junctions
South end	US 377 at the Texas state line
Major intersections	US 70 in Madill I-40 near Seminole US 62 in Prague I-44 / US 377 in Stroud US 64 in Cleveland US 60 / SH-11 in Pawhuska
North end	K-99 at the Kansas state line
Location
Country	United States
State	Oklahoma
Counties	Marshall, Johnston, Pontotoc, Seminole, Pottawatomie, Lincoln, Payne, Creek, Pawnee, Osage
Highway system
Oklahoma State Highway System Interstate US State Turnpikes
← SH-98 → SH-100
← SH-325 US-377 → US 385

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

SH-99 continues as 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).

SH-99 began as SH-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.