On September 26, 1945, the roadway was extended northwest to Breckenridge over SH 67, continuing northwest to near Throckmorton along SH 157, which was decommissioned. That same day, the section in southeast Texas between Hempstead and Sugar Land was cancelled, as it was redundant with the new Farm to Market Road 359. On August 20, 1952, the route was truncated on the north side, ending near Breckenridge. This section was transferred to U.S. Highway 183. On September 26, 1967, SH 6 was rerouted to bypass Bremond, with the old route through Bremond transferred to SH 14 and FM 46. On November 1, 1968, the section between Hempstead and Sugar Land was re-established, as it was routed along U.S. Highway 290 until it reached Farm to Market Road (FM) 1960, then replacing FM 1960 southward to where the southern branch of SH 6 intersected to what is now Interstate 69/U.S. Highway 59 in Sugar Land. That portion of FM 1960 from 290 to then Highway 90 at Addicks was built in the 1950s, replacing and rerouting some of what was known as Jackrabbit Road. In the early 1970s, the northern section underwent a massive rerouting due to realignments of numerous U.S. and state routes. On August 4, 1971, the section from Breckenridge south to Eastland was redesignated as State Highway 69. SH 6 was instead rerouted west along U.S. Highway 80 to Cisco, then replaced U.S. Highway 380 northwest to near Old Glory. The route was again extended on July 31, 1975, replacing State Highway 283 between Old Glory and Stamford northward to the Texas/Oklahoma border, completing the current routing of SH 6. The old route of SH 6 was transferred to new SH 283. On October 27, 1989, a section from US 90A to McKeever Road (McKeever Bypass) was added.