New England Interstate Route 12
|Length:||279.03 mi (449.06 km)
Connecticut: 54.46 mi (87.64 km)
Massachusetts: 64.41 mi (103.65 km)
New Hampshire: 62.64 mi (100.84 km)
Vermont: 97.53 mi (156.86 km)
|Existed:||1922 – 190s|
|South end:||US 1 in Groton, CT|
| US 6 in Killingly, CT
US 44 in Putnam, CT
Route 2 in Leominster, MA
NH 101 in Keene, NH
US 4 in Woodstock, VT
US 2 in Montpelier, VT
|North end:||VT 15A / VT 100 in Morrisville, VT|
New England Route 12 was a multi-state north–south state highway in the New England region of the United States, running from Groton, Connecticut, through Worcester, Massachusetts, and Keene, New Hampshire, to Morrisville, Vermont. Its number dates from 1922, when it was a New England Interstate Route, also known as the Keene Way. A multi-state "Route 12" still exists, bearing the names of the states through which it passes, and partially following the original alignment of the New England Route.
The southern terminus of Route 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, Connecticut to Claremont, New Hampshire, Route 12 still follows its 1920s alignment.
The original northern terminus was at Derby, Vermont. In the 1960s, the route was truncated and the northern terminus was moved to its present location at Morrisville, Vermont. The original route ran along what is now Vermont Route 14 from Montpelier to Hardwick, Vermont Route 16 from Hardwick to Barton, and U.S. Route 5 from Barton to Derby.
- Connecticut Route 12
- Massachusetts Route 12
- New Hampshire Route 12
- Vermont Route 12
- Vermont Route 12A - The road currently used by Vermont Route 12A was originally designated New England Interstate Route 12A in 1922 and existed as such until it was replaced by a different system in 1926.
- Vermont Route 14 - The northernmost section used to be New England Route 12B