Originally part of Route 89, Route 289 got its own number on Dec. 1, 1964, when Route 89 was truncated to the Route 195 junction in Mansfield. This was done so Route 195 would extend to Willimantic instead of 89, possibly to aid navigation to the University of Connecticut, on Route 195 in Storrs.

In Lebanon, south of Burnham Road, a small side road on Route 289 is still called "Old Route 89".

In 1935, today's Route 289 was known as the Beaumont Memorial Highway.

• "Highway numbering reassigned." The Hartford Courant, Dec. 8, 1964.

• Route 289 Ends (Photos; Doug Kerr at state-ends.com)
• Route 289 - Google Maps