The road from Parowan northeast through Paragonah and southwest through
Summit was added to the state highway system in 1910, and in the 1920s it became part of
SR-1 and
US-91. In 1968, with the construction of I-15 in the area imminent, SR-1 was moved to the proposed bypass, and the old route of SR-1 became
State Route 38 (I-15 near Summit to Center Street in Parowan),
SR-143 (Center Street to near 500 North in Parowan, and then continuing to I-15), and
State Route 76 (near 500 North in Parowan to I-15 near Paragonah). However, the state legislature did not concur with the latter, and the old road through Paragonah was maintained only until I-15 was completed. Construction of I-15 was finished by 1975, and included a second Parowan interchange that had not been in the 1968 plans. SR-143 was rerouted to turn south on SR-38 (old SR-1) in Parowan and west on 200 South to the new interchange, and the remainder of SR-38 was removed from the state highway system. (The 1968 extension of SR-143 was redesignated SR-274.) The road from Parowan through Paragonah to I-15 was restored to the state highway system in 1978 as SR-271. ==Major intersections==