 On November 4, 1971, an extension along Ranch to Market Road 2695 to US 287 along was signed, but not designated.On August 29, 1990 the current route was completed by redesignating Ranch to Market Road 2695 from McLean to SH 203 as part of SH 273.Beginning at a junction with US 60 at Pampa in Gray County, SH 273 runs south to a junction with Loop 171.