At Marias Pass, the Theodore Roosevelt Memorial Monument, a obelisk patterned after the Washington Monument, was built in 1931 to honor the 25th anniversary of the United States Forest Service. It originally stood right in the middle of the highway, with traffic flowing around it. In 1989, it was placed in a rest area/memorial park south of the highway, and the highway at the summit was widened to four lanes to allow slower vehicles to be passed before descending the pass.