US 44A was an alternate route to US 44, extending from the Wilbur Cross Highway (now I-84 in Manchester) to US 44 in Ashford. It was originally part of US 44, and is now part of US 44 today; the same route change that created US 44A in 1948 was reversed in 1982.
In 1948, the Wilbur Cross Highway was completed from East Hartford to Tolland, as a four-lane freeway connecting to the two-lane "Super 2" road continuing to Massachusetts. At the time, US 44 followed the same route it does today from Manchester through Ashford via Bolton, Coventry and Mansfield.
To encourage motorists to use a newer, more direct route, the state moved US 44 to the Wilbur Cross Highway, overlapping Route 15 from US 6 in Manchester to Route 74 in Willington. Then, US 44 replaced Route 74 east of that interchange, continuing to Ashford. The bypassed segment of US 44 became US 44A.
When I-84 was designated along the Wilbur Cross Highway, the overlap with US 44 carried three numbers: I-84 (later, I-86), US 44, and Route 15. Generally the interstate and state routes were well signed at interchanges, but US 44 was not. In 1980 the state shortened Route 15 to simplify things.