Route 372 begins at an intersection with Route 72 in western Plainville, near the Plainville-Bristol town line, and heads generally east. It intersects Route 177, then passes through the town center. It has a junction with Route 10 just before underpassing Route 72 with eastbound access provided by Hooker Street. At the New Britain, it passes under I-84 without an interchange, then turns southeast to intersect Route 72 again at Exit 7. It continues southeast, and intersects SR 571 at the Berlin town line. Eastbound traffic continues on one-way SR 918 to cross Route 71A, while westbound traffic briefly overlaps with Route 71A through the intersection. In the Kensington section of town, it intersects Route 71, and passes the Berlin Amtrak station. Just north of Berlin Center, it intersects Route 9 at Exit 22, the US 5/Route 15 concurrency, and Route 9 again at Exit 21 in rapid succession. It continues east through East Berlin and crosses the Mattabesset River into Cromwell. In Cromwell, it continues easterly along the Mattabesset River, intersecting I-91 at Exit 21. It then widens to 4 lanes, and intersects the northern end of Route 217. Farther east, it crosses Route 3 before meeting Route 9 once again at Exit 19. It then turns southeast to at an intersection with Route 99 at the Cromwell town center.
History
was established in the 1932 state highway renumbering between Route 66 in Middletown and Route 10 Plainville. By the beginning of 1963, after the implementation of the 1962 Route Reclassification Act, Route 72 was extended west and north through Bristol and Plymouth to Route 4 in Harwinton. A freeway along the Route 72 corridor between Berlin and Plainville was built beginning in the late 1950s and opened in stages beginning in 1961. By late 1980, the Route 72 freeway was fully open between the Berlin Turnpike and the current west end of the freeway in Plainville. With the extension of the Route 72 freeway in New Britain in 1978 and in Plainville in 1980, Route 372 was designated along the former surface route of Route 72. In 1980, Route 372 ran from the end of the Route 72 freeway in Plainville to Exit 24 of Route 9 in Berlin, including the Willow Brook Connector. In 1990, a freeway link between I-91 and the east end of the Route 72 freeway was completed. This resulted in the Route 9 designation being extended westward to Exit 28, Route 72 being truncated in the east to end at Route 9, the Willow Brook Connector being redesignated as SR 571, and Route 372 being rerouted and extended eastward along the former Route 72 in Berlin and Cromwell to Route 3. Additionally, Route 372 continued east to Route 99 along a former unsignedstate road.
