By undertaking a census of all agricultural, outdoor recreational, and environmental groups (land-based groups) in two adjacent counties in Vermont, we demonstrate the dramatic increase of local environmental groups in the last 15 years. Building on the methodologies of Kempton et al. (2001), we first show that official lists of nonprofit groups-from the Vermont Secretary of State, the Internal Revenue Service, and local grassroots directories-significantly undercount local environmental groups. Second, we show that since the mid-1980s, the number and membership roles of local autonomous environmental groups have grown rapidly relative to all other types of local and non-local land-based groups in these counties. This article provides preliminary evidence of the recent "greening of social capital."