- Southern Terminus:
- Kings Highway (US 1) in Fairfield
- Northern Terminus:
- Milwaukee Avenue (CT 302) in Bethel
- 18.58 miles
CT 58 is a north/south route in Fairfield County. It begins at Kings Highway (US 1) in Fairfield and runs northwest as Tunxis Hill Road for about half a mile before merging into Black Rock Turnpike, which is designated SR 732 south of this point. CT 58 follows Black Rock Turnpike north, having an interchange with the Merritt Parkway (CT 15) and then running along the west side of the Hemlock Reservoir. As CT 58 makes its way north, it changes names to become Black Rock Road and then Putnam Park Road. It ends at Milwaukee Avenue (CT 302) in Bethel.