Route 28 was originally formed as a New England interstate route established in 1922 to run from Buzzards Bay to New Hampshire. The route itself was overlaid on several early turnpike roads constructed in the early 19th century. Except for an extension into Cape Cod in 1926, the overall highway layout and routing is largely unchanged from its original design. Route 28 has been realigned in several places when newer, higher quality roads were built. At a length of nearly , Route 28 is the longest state-numbered highway in Massachusetts, and the second-longest highway, behind U.S. Route 20.