Route 117 is a 31.0718-mile-long (50.0052 km) east–west state highway in Massachusetts, running from Route 12 in Leominster in northeast Worcester County to U.S. Route 20 in Waltham in central Middlesex County.

Leominster is a city in Worcester County, Massachusetts, United States. It is the second-largest city in Worcester County, with a population of 43,222 at the 2023 census. Leominster is located north of Worcester and northwest of Boston. Both Route 2 and Route 12 pass through Leominster. Interstate 190, Route 13, and Route 117 all have starting/ending points in Leominster. Leominster is bounded by Fitchburg and Lunenburg to the north, Lancaster to the east, Sterling and Princeton to the south, and Westminster to the west.