| State: | OK |
| Type: | SH |
| Route: | 73 |
| Map: | Ok-73 path.png |
| Maint: | ODOT |
| Length Mi: | 24.5 |
| Direction A: | West |
| Direction B: | East |
| Terminus A: | north of Elk City |
| Terminus B: | in Clinton |
| Previous Type: | SH |
| Previous Route: | 72 |
| Next Type: | SH |
| Next Route: | 74 |
State Highway 73 (abbreviated SH-73 or OK-73) is a 24½ mi[1] (39.4 km) state highway mostly in Custer Co., Oklahoma, although a stretch of about four-fifths of a mile (1.3 km) of its eastbound lane lies in Roger Mills Co. SH-73 has no lettered spur routes.
State Highway 73 begins at State Highway 34 south of Hammon. The western terminus of the highway occurs at a jog in the Roger Mills–Custer county line; north of the intersection, SH-34 runs along the north–south boundary, and at the intersection, the boundary makes a ninety-degree turn to head east–west. The first 0.8miles of SH-73 straddles the county line.[2] The county line makes another turn after this to return to a north–south orientation, and SH-73 fully enters Custer County.
In Custer County, SH-73 travels through hilly terrain and crosses both Panther Creek and Little Panther Creek, tributaries of Foss Lake. SH-73 serves the southwestern portion of the lake, and runs along the edges of Foss State Park. The highway provides connections to four campgrounds along the lakeshore.[2] Near the southeast corner of the lake, the route intersects SH-44.
SH-73 turns south along SH-44, forming a concurrency. The two routes curve southwest to cross Oak Creek. SH-44/73 travel together for 2miles[3] before SH-73 splits off, returning to a due east course. The highway parallels I-40, which runs to the south of SH-73. SH-73 then bridges the Washita River. West of Clinton, the highway crosses a set of railroad tracks at the unincorporated locale of Ralph.[2] State Highway 73 then enters Clinton, where it comes to an end at an intersection with I-40's Clinton business loop.