The Oakdale Merge is a convergence of Sunrise Highway (New York State Route 27, NY 27) and Montauk Highway (NY 27A and County Route 85, CR 85) between the hamlets of Great River and Oakdale, in Suffolk County, New York, in front of Connetquot River State Park.

[1] The western at-grade interchange had a westbound-only ramp to Montauk Highway and an east-to-west U-turn to take motorists to the park entrance.

[1][9][10] Former segments of Montauk Highway now existed on both sides of the interchange, and both roads were converted into fishing areas owned by the New York State Department of Environmental Conservation.

[3][7][10][11] The current design of the interchange frequently causes congestion between Great River and Oakdale, has forced the use of convoluted routes to some destinations.

[1][9][10] The current design has also been criticized as frequently causing drivers to become confused & disoriented—in addition to it being a safety hazard: the east end of the merge has been the scene of numerous accidents, which have involved the access to the eastbound service roads from both directions on Montauk Highway.

[17][18] In January 2024, it was announced that Governor Kathleen C. Hochul's 2024 state budget would include further funds for studying how best to reconstruct the interchange.