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EnviroAtlas - Percent Large, Medium, and Small Natural Areas for the Conterminous United States

Published by U.S. EPA Office of Research & Development (ORD) - National Exposure Research Laboratory (NERL) | U.S. Environmental Protection Agency | Metadata Last Checked: January 27, 2026 | Last Modified: 2015-05-07T00:00:00.000+00:00
This EnviroAtlas dataset contains the percentage of small, medium, and large natural areas for each Watershed Boundary Dataset (WBD) 12-Digit Hydrologic Unit Code (HUC-12) of the conterminous United States that is considered Natural based on the National Land Cover Database (NLCD). The percentage of natural area is by size class: Small is <500 acres, Medium is 500-25,000 acres, and Large is > 25,000 acres. Natural land cover combines NLCD-CDL 63, 83, 87, 111, 112, 131, 141, 142, 143, 151, 152, 171, 190, 195. This dataset was produced by the Tetra Tech, Inc. to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

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