- Southern Terminus:
- Merritt Parkway (CT 15) in Trumbull
- Northern Terminus:
- Roosevelt Drive (CT 34) in Monroe
- 11.71 miles
CT 111 is a north/south route through Trumbull and Monroe. Main Street in Trumbull takes on the CT 111 designation at its interchange with the Merritt Parkway (CT 15). It runs north through Trumbull to the northern end of the expressway section of CT 25. There, Main Street turns northwest onto CT 25, while CT 111 continues north as Monroe Turnpike. In Monroe, there is a traffic circle at the northern terminus of Shelton Road (CT 110). Monroe Turnpike continues north to end at Roosevelt Drive (CT 34) near the Housatonic River.