Route 175 is a state highway in central Connecticut, running from New Britain to Wethersfield.

It heads east and north along the perimeter of Central Connecticut State University, then turns east again and intersects Route 9 at the Newington town line.

At the Wethersfield town line, it meets US 5 and Route 15 (Berlin Turnpike) at a grade-separated interchange, and continues east to end at an intersection with Route 99.

In 1968, a section in Newington and Wethersfield was rerouted slightly to the north.

Part of the old road was abandoned; the remainder was reassigned to modern SSR 405.