This coverage was developed from field surveys conducted on the mainstem and selected tributaries of the Aroostook, Dennys, Ducktap, East Machias, Kennebec, Machias, Passagassawakeag, Penobscot, Pleasant, Presumpscot, Saco, Sheepscot, St. George, Tunk and Union Rivers in Maine by staff of the Maine Dept. of Marine Resources - Division of Sea Run Fisheries and Habitat. These surveys were conducted to identify important Atlantic salmon habitat including spawning and rearing areas. The majority of the survey data was collected using Trimble Pro, Pro-XL and GeoExplorer3 receivers and survey files were differentially corrected to provide 2-5 meter accuracy. Surveys for some reaches were collected with minimal or no GPS control points and the attributes were overlaid on a stream centerline created using either a GPS-acquired line, a line derived from MEGIS/USGS 1:24,000 hydrography data, or a line drawn as a centerline based on MEGIS digital orthophotography. The dataset includes information on habitat categories and areas, and an indication of spawning and rearing potential. This data is referred to as Level 3, or detailed habitat survey data, to be contrasted with the Level 2 habitat data which contains the most detailed data for individual habitat units.