On March 19, 1930, the SH 20 designation was dropped over the Fredericksburg to Kerrville highway (replaced by an extended SH 81) and extended instead over the auxiliary route SH 20A. In 1933 the road was described between Fredericksburg and Hempstead as paved except for the portion in Hays County around Dripping Springs and a short portion west of Elgin that were described as surfaced. The portion west of Fredericksburg toward Junction was graded earth. In 1935, US 290 was routed over SH 20 except for the portion between Austin and Paige where US 290 was routed further south through Bastrop. By 1936, the formerly surfaced portion west of Elgin had been paved, but the Hays County portion remained merely surfaced. West of Fredericksburg, the Gillespie County portion had been surfaced while the Kimble County portion remained as an improved earth road. On September 26, 1939, the SH 20 designation was dropped along all portions of the route running along US 290 as a result of that day's general redescription of the state highway system, leaving SH 20 as a greatly shortened route running from Austin to US 290 near Paige. On May 23, 1951, US 290 was relocated away from Bastrop northward along SH 20 which was then decommissioned.