Medium resolution NHD areas

In the late 1990s, the USGS and the US EPA collaborated to produce the National Hydrography Dataset Medium Resolution, at 1:100,000 scale for the conterminous U.S. In the early 2000s, the US EPA assumed the role of primary custodian for the NHD Medium Resolution to support their applications and those of other medium resolution users, while the USGS, U.S. Forest Service, and additional partners initiated the production of the NHD High Resolution at 1:24,000 scale or better.