Route 318 is a state highway in northern Connecticut running entirely in Barkhkamsted.

Route 318 begins at an intersection with US 44 in Barkhamsted and heads east-northeast.

It overlaps Route 181, heading east, to cross the West Branch Farmington River, then continues east over the Saville Dam past Lake McDonough, ending at a "Y" intersection with Route 219.

SR 418 was first designated as a state road in 1937 from Route 181 to the Saville Dam.

[2] The entire route is in Barkhamsted, Litchfield County.