 New York State Route 347 | ||||
|---|---|---|---|---|
| Nesconset–Port Jefferson Highway | ||||
 Map of Suffolk County on Long Island with NY 347 highlighted in red | ||||
| Route information | ||||
| Maintained by NYSDOT | ||||
| Length | 14.48 mi[1] (23.30 km) | |||
| Existed | 1966[2]–present | |||
| Major junctions | ||||
| West end |   NY 454 / Northern State Parkway in Hauppauge | |||
 NY 111 in Hauppauge NY 25 in Nesconset CR 97 in Lake Grove NY 112 in Port Jefferson Station | ||||
| East end |  NY 25A in Mount Sinai | |||
| Location | ||||
| Country | United States | |||
| State | New York | |||
| Counties | Suffolk | |||
| Highway system | ||||
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New York State Route 347 (NY 347) is an east–west state highway located in Suffolk County, New York, in the United States. It connects the Northern State Parkway in Hauppauge to NY 25A in Mount Sinai. The route serves as a southern bypass of Smithtown and as a direct link between Nesconset and Port Jefferson, leading to the road being known as Smithtown Bypass in the Town of Smithtown, and for its entire length as the Nesconset–Port Jefferson Highway. Along the way, NY 347 intersects NY 25 in Nesconset and Nicolls Road (County Route 97 or CR 97) in Lake Grove. The westernmost 2 miles (3.2 km) of NY 347 is concurrent with NY 454 while the portion northeast of NY 25 parallels NY 25A, which follows a more northerly alignment through the Town of Brookhaven than NY 347.
The highway was built by Suffolk County in the 1950s and designated as part of two county routes. It gained a single designation in 1966 when the state of New York assumed ownership and maintenance of the highway and designated it as NY 347. Several proposals to extend or improve the highway have been developed in the years since; however, none have been implemented, mostly due to community opposition.