 SR 181 was first designated in 1923 along the majority of its current routing, excepting the portion that follows the former routing of US 30 in Crestline.The only significant change to its route occurred in 2006.After US 30 was relocated onto a new freeway bypass in that year, SR 181 was extended west along the former routing of the U.S. highway to SR 61 in downtown Crestline.