NMFS is designating critical habitat for two Evolutionarily Significant Units (ESUs) of coho salmon (Oncorhynchus kisutch) pursuant to the Endangered Species Act of 1973 (ESA). Critical habitat for the Central California Coast ESU encompasses accessible reaches of all rivers (including estuarine areas and tributaries) between Punta Gorda and the San Lorenzo River (inclusive) in California, including two streams entering San Francisco Bay: Arroyo Corte Madera Del Presidio and Corte Madera Creek. Critical habitat for the Southern Oregon/ Northern California Coasts ESU encompasses accessible reaches of all rivers (including estuarine areas and tributaries) between the Mattole River in California and the Elk River in Oregon, inclusive. The areas described in this final rule represent the current freshwater and estuarine range of the listed species. For both ESUs, critical habitat includes all waterways, substrate, and adjacent riparian zones below longstanding, naturally impassable barriers (i.e., natural waterfalls in existence for at least several hundred years). After considering public comments and reviewing additional scientific information, NMFS is modifying various aspects of the proposed designation, including a revised description of adjacent riparian zones and the exclusion of tribal lands from critical habitat. NMFS has identified several dams in the range of these ESUs that currently block access to habitats historically occupied by coho salmon. However, NMFS has not designated these inaccessible areas as critical habitat because the downstream areas are believed to provide sufficient habitat for conserving the ESUs. The economic (and other) impacts resulting from this critical habitat designation are expected to be minimal.