The Sunken Meadow State Parkway begins at exit 44–45 off the Northern State Parkway, a cloverleaf interchange that also serves as the northern terminus of the Sagtikos State Parkway. Southbound, this interchange is designed as exit SM1. After the Northern State, the Sunken Meadow continues northeast on the right-of-way used by the Sagtikos, crossing through Commack. Passing west of Valmont Village Park, the four-lane parkway crosses under New Highway, bending northeast through Commack, becoming a divided parkway as it enters exit SM2. This exit, which is only served northbound, connects the Sunken Meadow to NY 454 (Veterans Memorial Highway) via Harned Road, a local street in Smithtown. The four-lane parkway continues northward through Candy Section, crossing under NY 454 a short distance after the interchange. At the overpass, the westbound entrance from NY 454 connects to the southbound Sunken Meadow.