Interstate 90 (I-90) is a part of the Interstate Highway System that runs from Seattle, Washington, to Boston, Massachusetts. In the US state of New York, I-90 extends 385.48 miles (620.37 km) from the Pennsylvania state line at Ripley to the Massachusetts state line at Canaan, and is the second-longest highway in the state after New York State Route 17 (NY 17). Although most of the route is part of the tolled New York State Thruway, two non-tolled sections exist along I-90. Within New York, I-90 has a complete set of auxiliary Interstates, which means that there are Interstates numbered I-190 through I-990 in the state, with no gaps in between. For most of its length in New York, I-90 runs parallel to the former Erie Canal route, NY 5, US Route 20 (US 20) and the CSX Transportation railroad mainline that traverses the state.