Interstate 395 Southbound is closed between exits 79A and 79 in Montville because of two multi-vehicle crashes.
According to the state Department of Transportation, there is a 2.6 mile backup.
State police said one crash involves two cars and no injuries are reported. The other involves several cars, but no other details are yet available.
Lt. Paul Vance, of Connecticut State Police, said he does not think these are serious crashes and said he expects they will be cleared soon.