In the 1920s, State Highway 103 followed today's Route 14 from Route 12 into Rhode Island.

Commissioned in 1932, the old Route 103 was a 2.39-mile route entirely within Wilton, leading north from the Norwalk town line to a point 2.13 miles north of Route 33, along Chestnut Hill Road and Hurlbutt Street. In other words, it had two dangling ends (though town roads continued) and only intersected one other highway.

in 1963, the old Route 103 became part of today's Route 53.

The modern Route 103 was promoted from two secret routes on Dec. 24, 1987: SR 720 (north half) and SR 750 (south). Until the late 1960s, the north half was part of US 5A.

Route 103 Ends (Photos; Doug Kerr at state-ends.com)