Hudson is a census-designated place (CDP) comprising the densely developed central part of the town of Hudson in Middlesex County, Massachusetts, United States. The population of the CDP was 15,749 at the 2020 census, out of 20,092 in the entire town.

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.