US 113 follows the corridor of a post road established in the late 18th century to connect the aforementioned towns on the Delmarva Peninsula with Wilmington and Philadelphia. The highway was improved as an all-weather road in the 1910s. In Maryland, the post road was designated one of the original state roads established by the Maryland State Roads Commission (MDSRC) in 1909. In Delaware, the highway was the Selbyville–Dover portion of the DuPont Highway, a roadway whose construction was a grand philanthropic measure of Thomas Coleman DuPont. The DuPont Highway, which was started by DuPont's company and finished by the Delaware State Highway Department (DSHD), spurred economic growth in the tourism and agriculture sectors in southern Delaware. The economic growth resulted in heavy traffic; US 113 was widened in both states in the early 1930s and again in the late 1940s. Bypasses of Dover and Pocomoke City were built in the mid-1930s; the bypassed section of highway in Dover became US 113 Alternate.