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	I-95 / US 1 / Route 184 in Groton
Major intersections	Route 2A in Preston Route 2 in Norwich I-395 in Lisbon Route 14 in Central Village US 6 in Danielson I-395 / Route 101 in Dayville US 44 in Putnam
North end	Route 12 at the Massachusetts state line
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

Connecticut Route 12 is a state highway that runs from Groton north to the Massachusetts state line in Thompson.

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.

County	Location	mi	km	Destinations	Notes
New London	Groton	0.0	0.0	US 1 north – Groton City	Continuation north; southern end of US 1 concurrency northbound
		0.22	0.35	I-95 south / US 1 south / Route 184 east – New London, Providence, Ledyard	Exit 86 on I-95; western terminus and exit 1 on Route 184; northern end of US 1 concurrency northbound
	Ledyard	6.86	11.04	Route 214 east – Ledyard	Western terminus of Route 214
	Preston	9.08	14.61	Route 2A west to I-395 – Uncasville	Southern end of Route 2A concurrency
		9.38	15.10	Route 2A east – Hallville	Northern end of Route 2A concurrency
	Norwich	12.12	19.51	Route 2 west to Route 32 – Hartford	Southern end of Route 2 concurrency
		12.43	20.00	Route 2 east – Stonington	Northern end of Route 2 concurrency
		15.19	24.45	Route 97 north – Taftville	Southern terminus of Route 97
	Lisbon	19.62	31.58	I-395 – Worcester, New Haven	Exits 21A-B on I-395; former Route 52
		20.43	32.88	Route 138 west – Newent	Southern end of Route 138 concurrency
	Griswold	20.82	33.51	Route 138 east – Pachaug	Northern end of Route 138 concurrency
		21.05	33.88	Route 201 south – Hopeville Pond State Park	Northern terminus of Route 201
Windham	Canterbury	23.57	37.93	Butts Bridge Road (SR 668 west)
	Plainfield	26.60	42.81	To I-395	Access via SR 647
		27.50	44.26	Route 14A west – Plainfield, Canterbury	Southern end of Route 14A concurrency
		27.91	44.92	Route 14A east to I-395 – Sterling	Northern end of Route 14A concurrency
		30.31	48.78	Route 14 east to I-395 – Moosup	Southern end of Route 14 concurrency
		30.59	49.23	Route 14 west – Canterbury	Northern end of Route 14 concurrency
		32.12	51.69	Route 205 north – Wauregan, Brooklyn	Southern terminus of Route 205
	Killingly	36.15	58.18	US 6 east to I-395 – Providence	Southern end of US 6 concurrency
		36.51	58.76	US 6 west – Hartford	Northern end of US 6 concurrency
		37.19	59.85	To I-395	Access via SR 607
		39.46	63.50	I-395 / Route 101 – Dayville, East Killingly	Exit 41 on I-395
		42.04	67.66	Route 21 north – Putnam Heights	Southern terminus of Route 21
	Putnam			I-395 – Thompson, Webster, MA	Access via Heritage Road; exit 46 on I-395; former Route 52
		45.58	73.35	US 44 west – Pomfret	Southern end of US 44 concurrency
		46.02	74.06	Route 171 west – Woodstock	Eastern terminus of Route 171
		46.22	74.38	US 44 east to I-395 – East Putnam	Northern end of US 44 concurrency
	Thompson	48.17	77.52	Route 193 north – Webster, MA	Southern terminus of Route 193
		48.88	78.66	I-395 south – Norwich, New Haven	Exit 49 on I-395; former Route 52
		49.88	80.27	Route 200 east – Thompson	Western terminus of Route 200
		51.95	83.61	Route 131 west – Quinebaug, Southbridge, MA	Eastern terminus of Route 131
		54.46	87.64	Route 12 north – Auburn, Worcester	Continuation into Massachusetts
1.000 mi = 1.609 km; 1.000 km = 0.621 mi

Media related to Connecticut Route 12 at Wikimedia Commons

• Route 12 at Connecticut Roads