As CR 809A, Northlake Boulevard crosses the southernmost portion of Palm Beach Gardens and the northernmost corner of West Palm Beach, beginning at an intersection with Seminole Pratt Whitney Road, in the wetlands north of Loxahatchee.

[2][3] State Road 850 begins at the intersection of State Road 811 and Northlake Boulevard, with Northlake Boulevard serving as the border between Lake Park to the south and North Palm Beach to the north.

[2][3] On December 19, 2017, the Palm Beach County Board of Commissioners approved a transfer agreement to submit to the Florida Department of Transportation,[4] which would transfer SR 850 to county maintenance.

In May 2018, the transfer was completed, effectively deleting SR 850 from the state highway system.

The county has not announced if they intend to maintain the 850 designation, or add it to CR 809A.