National Hydrography Dataset (NHD)

The National Hydrography Dataset is designed to provide comprehensive coverage of hydrologic data for the US. While based on 1:100,000-scale data, the National Hydrography Dataset is designed to incorporate--and encourage the development of--higher-...
Medium resolution NHD data are available at 1:100,000 scale for the conterminous US and Hawaii. High resolution NHD data are available for Puerto Rico at 1:20,000 scale and the Virgin Islands at 1:24,000 scale. In addition, data for Alaska are being...