Skip to main content
U.S. flag

An official website of the United States government

National Wetlands Inventory products

January 1, 1998

Marshes, swamps, ponds, and bogs are teeming biological nurseries for migratory birds, fish, and aquatic plants. They also provide natural flood and erosion
control. These predominantly wet areas, or wetlands as they are commonly called, now represent only about 5 percent of the land surface of the lower 48 States. Out of 221 million acres of wetlands that once existed in the conterminous United States, the U.S. Fish and Wildlife Service (FWS) estimates that only about 103.3 million acres remain.


Each year, development, drainage, and agriculture eliminate another 290,000 acres-an area a little less than half the size of Rhode Island. From the 1950's to the 1970's, conversion of wetlands to farmland caused 87 percent of all wetland losses.


The FWS has long recognized the importance of America's wetlands because they form breeding and wintering grounds for great numbers of migratory birds. In 1977, the FWS began the National Wetlands Inventory (NWI), a systematic effort to classify and map America's remaining wetlands.

Publication Year 1998
Title National Wetlands Inventory products
DOI 10.3133/fs19195
Authors
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Fact Sheet
Series Number 191-95
Index ID fs19195
Record Source USGS Publications Warehouse