This book explores the influence of the Mississippi River drainage system on the Northern Gulf of Mexico between Mobile Bay, Alabama, and Sabine Pass, Texas. Through geological time, this coastline has ranged from 250 miles offshore to North Louisiana. The present coastline consists of numerous barrier islands, bays and the most extensive saline, brackish, intermediate, and fresh marsh communities in the United States. It is currently eroding because of a lack of sediment input, subsidence, and numerous dredged canals. However, as noted here, efforts to remediate the coastline are expensive and problematic, and, as a result, this highly productive, shellfish-producing coastal region of the continental United States is regularly subjected to excess nutrients from the Mississippi River and was terribly stressed by the Macondo oil leak.