It crosses two arms of Lake Sam Rayburn before reaching its eastern terminus at SH 21 just west of Milam, and 10 miles from the Louisiana state line.

[4] By 1933, the route had only been built between Crockett and Ratcliff, and was only an improved earth road.

By 1940, sections around Lufkin were completed, but did not connect to earthen roads to the west.

On January 22, 1940, the section of SH 103 from Ratcliff to the Neches River was cancelled.

On March 26, 1942, SH 103 was extended west 3.5 miles from the Neches River.