Connecticut Route 12 is a state highway that runs between Groton and the state line in Thompson.

Quick Facts Route 12, Route information ...

Route 12
Map of eastern Connecticut with Route 12 highlighted in red
Route information
Maintained by CTDOT
Length	54.46 mi[1] (87.64 km)
Existed	1922–present
Major junctions
South end	US 1 in Groton
Major intersections	I-95 / Route 184 in Groton Route 2A in Preston Route 2 in Norwich I-395 in Lisbon Route 14 in Central Village US 6 in Danielson Route 101 in Dayville US 44 in Putnam
North end	Route 12 at Dudley, MA
Location
Country	United States
State	Connecticut
Counties	New London, Windham
Highway system
Connecticut State Highway System Interstate US State SSR SR Scenic
← Route 11 → Route 14
← Route 11 N.E. → Route 12A

Close

Route 12 was preceded by New England Interstate Route 12. The southern terminus of NE-12 was originally at New London, Connecticut. It travelled along present-day Route 32 (along the west bank of the Thames River) from New London to Norwich, Connecticut. In 1932, when Connecticut decommissioned its New England Routes, Route 12 swapped places with Route 32 south of Norwich. From Norwich to the Massachusetts border, Route 12 still follows its 1920s alignment.

Route 12 from Groton to Norwich is a primary route, serving the Naval Submarine Base New London and is known as the U.S. Submarine Veterans Memorial Highway. North of Norwich, Route 12 is a minor road closely paralleling Interstate 395. Route 12 goes through the following towns: Groton, Ledyard, Preston, Norwich, Lisbon, Griswold, Canterbury (0.14 miles only), Plainfield, Killingly, Putnam, and Thompson.