The corridor of SH 161 and the Turnpike was first proposed as an outer loop within Dallas County in 1957. The 1964 plan was the first to designate it as a freeway, and in 1969 the full loop was added to the state highway system as Loop 9. The loop would begin at Interstate 20 just east of the Tarrant County line and head north (along a corridor still planned as an extension of SH 161). From State Highway 183 it would run roughly along present SH 161, turning north on Belt Line Road and east just south of the Denton County line, crossing Interstate 35E near the present junction. Rather than cross into Denton and Tarrant Counties, the loop would stay in Dallas County, running roughly where Campbell Road is now. It would rejoin the present Turnpike alignment and head southeast to Interstate 30 west of Lake Ray Hubbard. The south part of the loop would continue in a roughly circular route to end at the junction of Interstate 20 and Spur 408, several miles east of the beginning of the loop. The short Spur 484, designated in 1970, would run from Loop 9 at Belt Line Road northeast along the present Turnpike alignment to Interstate 635.