Ohio 12-digit Subwatersheds

Download 12-digit watershed boundaries (shape file format)

Note:  The 12-digit Watershed Boundary Dataset (WBD) replaces the 14-digit layer.  It is a revised and enhanced 14-digit dataset.  Changes occurring between the 14 and 12-digit versions include the following:

  • Numeric coding in the new version added 2 digits to specify each smaller (finer) watershed delineation, rather than 3 digits.  e.g. 8-digit subbasins were subdivided into 10-digit watersheds and 10-digit watersheds were subdivided into 12-digit subwatersheds rather than the former 8, 11 and 14-digit sequence.
  • To provide more consistency in size of subwatershed, some 14-digit subwatersheds were aggregated for the 12-digit layer.  (No change in size or boundary occurred changing between the 11-digit and 10-digit portions of the WBD.)
  • The coding scheme was revised to provide more consistency across state boundaries.
  • Boundary delineations found to be in error were corrected.

The 14-digit layer is still provided as legacy data for continuity with older projects.  Information, status and history of the WBD can be found at  The 12-digit layer for Ohio can also be found at by going to the Ohio data portion of the website.  The layer from the "datagateway" site contains the base data for the national WBD.  The layer linked at the top of this page has a few additional, Ohio added, fields.