It is a 9.9-mile (15.9 km) mostly freeway alternate route of Route 2 that bypasses the downtown area of the city of Norwich and serves as the main access road to the Mohegan Sun casino.

Route 2A travels south along I-395 for 3.7 miles (6.0 km) before separating as its own four-lane freeway at I-395 Exit 9 in Montville.

It runs easterly for about 3.2 miles (5.1 km) with interchanges for Route 32 and Mohegan Sun Casino before becoming a two-lane freeway, after which it crosses the Thames River on the Mohegan-Pequot Bridge into Preston and ends at Route 12.

When the highway and bridge opened in December 1967, motorists were charged a 15-cent toll.

The toll plaza located at the west end of the Mohegan-Pequot Bridge was removed in 1980.