The route in New England and New York was designated as New England Interstate Route 5, part of the New England Interstate way system that existed between 1922 and 1927.
Around 1923, from Springfield to Pittsfield, NE-5 was known as "Jacob's Ladder". At what time US 20 was first specially made, it took over the entire of NE-5.
The 1953 Massachusetts Department of Public Works Master sketch would have relocated U.S. 20 between Palmer, Massachusetts and also West Springfield, Massachusetts or Westfield, Massachusetts along the right-of-way now used by the Massachusetts Turnpike, however this was never implemented.
Until 1970-72, Route 20 followed an old route throughout downtown Springfield - Boston Road also State Street - crossing the Connecticut River by the older Memorial Bridge (now Massachusetts Route 147).
The construction of Interstate 291 prompted modifies. Route 20 now crosses from West Springfield at the North End Bridge, in addition to is co-signed with I-291 until Page Boulevard, wherever it heads back to Boston Road by the former route of 20A