Nesconset Highway (NY-347)

The front entrance to the Smith Haven Mall.
Smith Haven Mall in Lake Grove, located directly on Route 347 at its junction with Middle Country Road (NY-25). The mall is one of Long Island’s largest shopping centers and a central landmark along NY-347, highlighting the highway’s role as both a commuter route and a busy commercial corridor. File photo: Jaclyn Vernace, licensed.

New York State Route 347 (NY-347), known locally as the Nesconset Highway, is a major east–west state highway in northern Suffolk County, Long Island. Spanning about 15 miles, it connects Smithtown to Port Jefferson Station, paralleling NY-25 (Jericho Turnpike) as a faster and more modern commuter route.

Built in the 1960s during the post-war suburban boom, NY-347 was intended to relieve congestion from Jericho Turnpike by providing a divided multi-lane highway through the mid-island corridor. Today it is lined with shopping centers, office parks, and medical facilities, making it both a commuter route and a commercial hub.

Route and Features

  • Western Terminus: NY-25 (Jericho Turnpike) in Smithtown
  • Eastern Terminus: NY-25A in Port Jefferson Station
  • Length: ~15 miles
  • County: Suffolk
  • Character: Multi-lane divided arterial, heavily trafficked commercial corridor
  • Restrictions: Open to all vehicles (not a parkway)

Major Intersections & Interchanges (west → east)

JunctionDestination / Notes
NY-25Smithtown — Western terminus
Sunken Meadow State ParkwayProvides north–south link to LIE & Sunken Meadow State Park
NY-111Hauppauge — connects to LIE and Islip
NY-454 (Veterans Memorial Highway)Hauppauge government offices / Islip MacArthur Airport
CR-97 (Nicolls Road)Stony Brook University / Lake Ronkonkoma / Patchogue
CR-83 (Patchogue–Mt. Sinai Rd)Farmingville / Mount Sinai
NY-25APort Jefferson Station — Eastern terminus

Notable Facts

  • Parallels Jericho Turnpike (NY-25): Serves as a modern, faster alternative for east–west travel in north-central Suffolk.
  • High traffic volume: Handles well over 60,000 vehicles daily, making it one of Long Island’s busiest state routes.
  • Commercial corridor: Lined with shopping plazas, corporate parks, and Stony Brook Medicine facilities.
  • Smart Corridor project: NYSDOT is transforming Route 347 with safer intersections, expanded turning lanes, bike lanes, sidewalks, and landscaping to balance commuter and community needs.
  • Commuter link: Provides critical access between Stony Brook University, Port Jefferson ferry terminal, Hauppauge’s government/commercial centers, and Islip MacArthur Airport.