Community composition data from multi-pass electrofishing surveys for assessing fish populations in headwater streams of the Adirondack Mountains, New York, USA. Each row represents one individual fish. This spreadsheet contains 11 columns. The first 7 columns describe the data (year collected, local site ID, stream name, latitude, longitude, USGS site number, and electrofishing pass number) and the remaining 4 columns describe each individual fish (common name, scientific name, total length (mm) and weight (g)). These data support the following publication: Baldigo, B.P., Sporn, L.A., George, S.D., and Ball, Jacob, in press. Efficacy of environmental DNA to detect and quantify Brook Trout Salvelinus fontinalis, populations in streams of the Adirondack Mountains, New York. Trans. Amer. Fish. Soc. na, na; http://dx.doi.org/10.1577/.