Route 111 (NY-111)

New York State Route 111 is a north–south state highway in central Suffolk County, Long Island, extending approximately 9.4 miles through the towns of Islip and Smithtown. The route was originally designated during New York’s 1930 statewide highway renumbering and was later realigned in 1966 to better serve the Islip area
Route 111 is a north–south state highway in central Suffolk County extending approximately 9 miles through the towns of Islip and Smithtown. The route was originally designated during New York’s 1930 statewide highway renumbering and was later realigned in 1966 to better serve the Islip area. File photo: Patrick Hatt, licensed.

New York State Route 111 (NY-111) is a major north–south roadway in central Suffolk County, Long Island. Extending from the South Shore community of Islip northward through Brentwood, Hauppauge, and into Smithtown, the route serves as an important commuter and commercial corridor connecting residential neighborhoods, industrial districts, and major regional highways.

NY-111 plays a critical role in linking central Suffolk County’s suburban communities with employment centers, shopping districts, and transportation infrastructure. The roadway provides direct access to key east–west routes including the Southern State Parkway, the Long Island Expressway, and the Sunken Meadow State Parkway, making it a heavily traveled artery for both local residents and regional commuters.

Route and Features

  • Southern Terminus: Montauk Highway (NY-27A) in Islip
  • Northern Terminus: NY-25 / Jericho Turnpike in Smithtown
  • Length: Approximately 12 miles
  • County: Suffolk
  • Character: Multi-lane suburban arterial with residential, industrial, retail, and commuter traffic
  • Restrictions: Open to passenger and commercial vehicles

Major Intersections & Interchanges (south → north)

JunctionDestination / Notes
NY-27A (Montauk Highway)Islip — Southern terminus
NY-27 (Sunrise Highway)South Shore east–west highway connection
Southern State ParkwayMajor commuter parkway interchange
I-495 (Long Island Expressway)Access to regional east–west travel corridor
NY-347 (Nesconset Highway)Connection to major commercial and commuter route
NY-25 (Jericho Turnpike)Smithtown — Northern terminus

Vicinity of the Roadway

Notable Facts

  • Central Suffolk connector: NY-111 serves as one of the primary north–south routes through central Suffolk County, connecting South Shore communities with inland business and residential districts.
  • Industrial and business access: The roadway provides important access to office complexes, warehouses, and industrial parks in Hauppauge, one of Long Island’s largest business and industrial centers.
  • Commuter corridor: Heavy daily traffic volumes reflect the route’s role in linking suburban neighborhoods with major employment hubs and parkway systems.
  • Retail and residential mix: Portions of the roadway transition between residential neighborhoods, shopping centers, and commercial districts, particularly through Brentwood and Hauppauge.
  • Regional highway access: NY-111 connects directly with several of Long Island’s most heavily traveled parkways and expressways, making it an important feeder route for regional traffic.
  • Daily-use roadway: The route functions as a vital transportation link for commuters, school traffic, shopping, and local business activity throughout central Suffolk County.

Route 111 (NY-111) remains one of the most important north–south transportation corridors in central Suffolk County, linking South Shore communities with major commercial districts, industrial centers, and regional highways. From local shopping trips and school traffic to business commuting and freight movement, the roadway plays a central role in the daily transportation network of Long Island’s suburban core.