Ocean and Coastal Development Impact Assistance Block Grant Act - Establishes the Ocean and Coastal Development Impact Assistance Fund in the Treasury. States that four percent of all bonus revenues and six percent of all royalty revenues from Outer Continental Shelf oil and gas leases shall be deposited in such Fund.

Provides block grants from such Fund to coastal States and territories for ocean and coastal energy impact assistance and resource management. Sets forth an allocation formula based upon oil or gas production, coastal population, and shoreline.

Requires a State to give at least 40 percent of such grant to local coastal communities.

Provides for assessment and audit of such block grants.