State Highway 51, abbreviated to SH-51 or OK-51, is a major state highway in Oklahoma, United States. It runs for east–west across the state, running from the Texas state line to Arkansas. It is the third-longest state highway in the system. Route description Texas to I-35 SH-51 begins at the Texas line concurrent with US-60 just east of Higgins, Texas. It remains concurrent for 61 miles (98 km) until it reaches US-270/US-281/SH-3 at Seiling, Oklahoma. At Seiling, SH-51 joins with those three highways for nine miles (14 km) before splitting off on its own. after splitting off, Highway 51 meets SH-58 in Canton. It then continues east, crossing the North Canadian River and meeting SH-51A before turning northeast toward Okeene, where it intersects SH-8. SH-51 will go for before intersecting another highway. In Hennessey SH-51 meets US-81 before continuing eastward. later, it meets SH-74 north of Crescent. to the east, it shares a brief concurrency with US-77; later it has an interchange at Interstate 35 at Exit 174. I-35 to Tulsa After crossing I-35, SH-51 becomes a multilane highway and a major corridor linking I-35 to Stillwater, the home of Oklahoma State University. Along this stretch is an intersection with SH-86. When SH-51 reaches Stillwater, it meets US-177. Continuing east from Stillwater, the road returns to a two-lane highway after sharing a concurrency with SH-108 and intersects with SH-18 later. east of this, it passes through Yale, Oklahoma before crossing SH-99. It becomes a multilane highway again after SH-48. It turns into the "Mannford Freeway" before passing through the small towns of Mannford and Lotsee on its way toward the Tulsa area. Tulsa and beyond In Sand Springs, SH-51 crosses the Arkansas River with SH-97 before merging onto the Sand Springs Expressway (US-412/US-64). When this freeway ends at I-244 near downtown Tulsa, SH-51 merges onto I-244 southbound only to exit later, where it runs concurrent with US-64/US-75. This freeway is actually Interstate 444, but the route is not signed as such. After one more mile, SH-51 leaves the interstate with US-64 and becomes the Broken Arrow Expressway, a freeway running northwest–southeast through Tulsa which is known as "The BA" by locals and local media. US-64 leaves the freeway as a concurrency with US-169 southbound. Later, SH-51 will exit the freeway and become a four-lane highway toward Coweta. The mainline freeway becomes the Muskogee Turnpike. At Coweta, SH-51 turns back east