SR 17 travels through parts of Franklin, Oxford, Androscoggin, Kennebec, Lincoln and Knox counties.

It then enters Oxford County at Byron, and continues south through Roxbury and into Mexico where it intersects US 2.

It then runs westerly concurrent with US 2 through Mexico and Dixfield 16.79 miles (27.02 km) until it leaves US 2 near the border of Oxford County and re-enters Franklin County, where it runs westerly until it connects with SR 4 in Jay.

Once over the river it then turns south leaving all other routes except concurrent with SR 9 for a short distance before turning east and continuing into Windsor where it concurs with SR 32.

And finally on into Rockland, where it terminates at US 1 and 1A close to the waterfront port and the Atlantic Ocean.