Route 17 officially begins about 0.1 miles (0.16 km) west of its interchange with Interstate 91 (at Exit 8).

Just after the bridge, it spawns a 3.02-mile-long (4.86 km) alternate, Route 17A, which leads to the center of town.

[1] The southern surface section from New Haven to Middletown is also known as George Washington Memorial Highway.

The 0.6-mile (0.97 km) freeway section from South Main Street to Route 9 in Middletown is known as the Catholic War Veterans Memorial Highway.

By 1922, Connecticut had numbered roads that were maintained by the state, which included all of modern Route 17.

[2][3] In the 1932 state highway renumbering, the road from New Haven to Glastonbury became part of the newly established Route 15.