HIFLD OPEN Outer Continental Shelf (OCS) Lease Blocks

Outer Continental Shelf (OCS) blocks serve as the legal definition for BOEM offshore boundary coordinates used to define small geographic areas within an Official Protraction Diagram (OPD) for leasing and administrative purposes. These polygons are clipped to the Submerged Land Act Boundary and Continental Shelf Boundaries. OCS blocks relate back to individual Official Protraction Diagrams (OPDs) and are not uniquely numbered. A block is uniquely described by the Protraction Number and Block Number (e.g., NK18-02, Block 6822). A full OCS block is 4800 x 4800 meters. Smaller, clipped aliquots are found along the Federal/State OCS boundary and along UTM zone borders. Only the most recently published paper or PDF versions of the OPDs or Supplemental Official Block Diagrams (SOBDs) should be used for official or legal purposes. These data were created in the applicable NAD83 UTM or NAD27 UTM/SPCS Projection and re-projected to GCS WGS84 (EPSG 4326) for management in BOEM's enterprise GIS. However, this service in this collection has been published in WGS 1984 Web Mercator Auxiliary Sphere (EPSG 3857). Because GIS projection and topology functions can change or generalize coordinates, these data are NOT an OFFICIAL record for the exact boundaries. These data are to be used for Cartographic purposes only and should not be used to calculate area.