Counties Passed through: Finney, Gray, Ford, Edwards, Stafford, Reno, Harvey, Marion, Chase, Lyon, Coffey, Osage, Franklin, Douglas
By 1932, US 50S was already hard-surfaced for a significant distance, with the only segments not hard surfaced being between northeast of Newton to Cottonwood Falls, and between the Lyon/Coffey County Line and Ottawa. Also, at the junction with US 75, 50S followed US 75 to just south of Lyndon, then headed east through Quenemo and Pomona to Ottawa.
By October, 1935, a new hard-surfaced alignment was built between Strong City and Elmdale, bypassing Cottonwood Falls.
In a resolution dated December, 1939, the south junction of US 50S and US 59 was re-aligned, eliminiating a railroad grade crossing on the south side of Ottawa.
US 50S was hard-surfaced in its entirety by 1941.
In a resolution dated June of 1946, US 50S was designated on a new alignment 1/2 mile to the north for 4 miles to the west. A December 1948 resolution did the same for 6 miles to the east of Emporia, and a September 1950 resolution extended the eastern realignment for another 4 miles to the Coffey County line. These relocations were completed by 1953.
A bypass to the North of Emporia had been shown as proposed as far back as the June 1946 resolution. In October 1950, a resolution officially designated the proposed bypass as part of US 50S. The bypass would be eventually be completed and designated I-35.