Route 117 is a state highway in southeastern Connecticut, running from Groton to Preston.

[1] Route 117 begins at an intersection with US 1 in the village of Poquonnock Bridge in Groton.

It intersects with Route 214 in Ledyard Center then continues north for another 3.2 miles (5.1 km) until the town line with Preston.

In 1959, SR 588 was extended north using the Colonel Ledyard Highway to the village of Poquetanuck.

One year later, the Route 117 designation was extended south to US 1 using a newly constructed extension of North Road.