County routes in Nassau County, New York, are maintained by the Nassau County Public Works Department. Route numbers were originally posted on unique blue-on-orange pentagonal route markers reflecting the county's official colors; however, all county route signage was removed in the mid-1970s after the Federal Highway Administration enacted new standards for county route markers in 1973. The county legislature opted not to appropriate funds to replace the signs with new markers conforming to the administration's Manual on Uniform Traffic Control Devices, leaving the routes unsigned. The route numbers are still used by the county for internal purposes only.
Route numbers, lengths, and termini are derived from the New York State Department of Transportation's county road listing for Nassau County unless otherwise noted. As all county routes are unsigned and the numbers are used for internal purposes only, information on Nassau County routes is limited; thus, the following list is likely incomplete.
This list of county routes (derived from the New York State Department of Transportation's county road listing for Nassau County) have designations that begin with a letter, followed by a number. As all county routes are unsigned and the numbers are used for internal purposes only, information on Nassau County routes is limited; thus, the following list is likely incomplete.