Route 176 was commissioned in 1932, and was originally a straight north and south road, following Main Street in Newington from the Berlin Turnpike, and South Street in West Hartford to end at New Britain Avenue (old Route 71). The Hartford Avenue part of today's Route 176 was actually part of Route 175, and the routes overlapped between there and Cedar Street.

In 1940, Route 175 was moved to its current location, Route 176 was shifted to its current location including Hartford Avenue, and a new Route 176A was created for the former 176 northward. Both 176 and 176A extended to New Britain Avenue, which by then was part of US 6.

In 1956, the Newington Chamber of Commerce discussed pursuing, as part of regional transportation plans, a widening of Route 176; but the road remains two lanes wide today.

In the route reclassification of 1962, the state intended to delete Route 176 and return it to the town -- and in fact, the route was omitted from the state map in 1965 through 1969. By 1972, however, Route 176 was back on the map, and remains there today.

It appears the result of arbitration was that Hartford accepted its part of Route 176 during the reclassification, leading to the end of state maintenance and the route designation at the city line.