U.S. population growth in coastal watershed counties has been most significant over the past 40 years in urban centers such as Puget Sound, San Francisco Bay, southern California, Houston, South Florida and the northeast metropolitan corridor. A coastal watershed county is defined as one where either 1) at a minimum, 15% of the county’s total land area is located within a coastal watershed, or 2) a portion of or an entire county accounts for at least 15% of a coastal USGS 8-digit cataloging unit.169c5207-212f-4c69-9055-c73621c44c36 Residents in these coastal areas can be considered “the U.S. population that most directly affects the coast.”169c5207-212f-4c69-9055-c73621c44c36 We use this definition of “coastal” throughout the chapter unless otherwise specified. (Data from U.S. Census Bureau).