In the 20th Century, the Interurban passed through Cumberland along the south side of Washington Street, and the Town continued to grow as a community closely tied to the National Road and transportation.
Buckley's Restaurant, which opened as a roadside Bar-B-Q stand in 1922 and became famous throughout Indiana and beyond, gave Cumberland some claim to fame through the early 1960's.
The Town was incorporated in 1951, and the first Town Board was elected at that time. Public water supply was developed in 1959, and the sanitary sewer system was originally constructed in 1966. In 1968, Cumberland Heights subdivision was annexed as part of the Town, and started the Town's expansion into Hancock County. Virtually all of the Town's future development will occur in Hancock County since Unigov legislation, adopted in 1970, has prevented the Town from expanding town boundaries in Marion County.
Cumberland's population grew by 20.6% from 1990 to 2000, from 4,557 to 5,500 residents, and today the community contains an estimated 6,000 residents, split almost equally between Marion and Hancock Counties.