The route proceeds northeastward as a four-lane commercial arterial, crossing an at-grade interchange with NY 111 (Hauppauge Road).

In Nesconset, NY 347 becomes a four-lane wooded arterial before passing east of Village of the Branch, where homes surrounded the highway from connecting roads.

The route bends to the east, crossing through Nesconset, then to the northeast and enters an at-grade interchange with NY 25 (Middle Country Road).

Crossing into the Saint James section of Smithtown, NY 347 continues to the northeast as the four-lane commercial arterial, now known as Nesconset Highway.

In the second entrance of Lake Grove, NY 347 intersects with CR 97 (Nicolls Road), which continues south as an eight-lane limited-access highway.

Crossing power lines, the route enters the hamlet of Terryville, and soon into Port Jefferson Station, where it intersects with NY 112 (Patchogue Road).

After passing near the yard for the Port Jefferson Branch of the Long Island Rail Road before merging into the right-of-way with NY 25A (Hallock Avenue) in Mount Sinai.

[2] Suffolk County hoped that by transferring jurisdiction to the state, it would be easier to upgrade the road into the limited-access highway as was originally intended.

[13] Design elements included stone arch and stone-faced overpasses, earthen berms as soundwall protection, and separate, dedicated space for a bike path.

[8] Originally, the state of New York had planned on building a spur between the Long Island Expressway (Interstate 495) and Smithtown Bypass.

[citation needed] A very faint vestige lives on, however, in the Rocky Point Bypass section of NY 25A,[23] which was constructed in the late 1990s.

[citation needed] Soon after the state of New York assumed ownership of the roadway in 1966, plans were immediately developed to improve it to a limited-access highway flanked by service roads.

When the Smith Haven Mall was built in 1969, it became a major retail attraction for those Long Islanders living east of Huntington.

The success of the mall spurred further commercial and residential development along NY 347, effectively killing the proposed upgrade to the highway.

The combination of Brookhaven's policies and NYSDOT's budget woes lead to the construction of many buildings that would had to have been razed in order to improve the highway.

The parcels alongside most of NY 347 were strip zoned for commercial properties, allowing the rapid development to take place.

McNamara took over the reconstruction of the shopping center in the late 1980s as part of an effort to revitalize it, dismantling of the service road in the process.

His project failed, but eventually it was discovered that he was bribing various government officials in the town of Brookhaven, Suffolk County, village of Port Jefferson, and even NYSDOT.