Atmospheric mercury research began at the Underhill, Vermont Air Quality Site in 1992 sponsored by EPA and NOAA. The site, hosted by the University of Vermont Proctor Maple Research Center and the Vermont Monitoring Cooperative became a focus for research on the atmospheric chemistry, deposition and ecosystem cycling of mercury in New England. A community of mercury researchers from Vermont and New England contributed to and made effective use of the first decade of wet deposition measurements and ecosystem studies focused on Underhill and the Lake Champlain Basin. In 2003, these researchers worked together to set goals for the second decade of atmospheric mercury research at Underhill that began with this project. The primary objectives of this project were to: (1) continue year-round monitoring of mercury wet-deposition in the Lake Champlain Basin; (2) establish measurements of speciated (gaseous elemental mercury (GEM), reactive gaseous mercury (RGM), and particulate mercury (HGP)) ambient atmospheric mercury; (3) conduct measurements of surface-atmosphere exchanges of GEM over a New England forest; and (4) evaluate possible pathways for assimilation of atmospheric mercury into the biota of terrestrial ecosystems of the region.