- Southern Terminus:
- Washington Street (CT 66) in Middletown
- Northern Terminus:
- CT 2 in East Hartford
- 14.48 miles
- Middlesex, Hartford
CT 3 is a north/south route extending from Middletown to East Hartford. It begins at Washington Street (CT 66) and runs north as a surface road through Cromwell and Rocky Hill to Wethersfield. There, it has an interchange with I-91 and becomes an expressway. It crosses a bridge over the Connecticut River and then promptly ends at the CT 2 expressway.
Prior to the construction of the CT 72 expressway, CT 72 followed what is now CT 372, SR 524, and CT 3 to end at Washington Street (CT 66). In those days, CT 3 ended at CT 72 in Cromwell.