Agriculture is one of the primary drivers of biodiversity loss. One agricultural policy instrument in this context is the spatial coordination of conservation efforts by farmers through ecological network projects, which represent spatially connected conservation areas, such as areas under agri-environmental schemes. However, the success factors for establishing ecological network projects, as well as their effects on various economic and ecological outcomes, are still poorly understood. To obtain a deeper understanding of these important questions, we assembled a novel and comprehensive geospatial dataset of network project perimeters at the municipality level in Switzerland. The dataset covers 98% of Switzerland's total land surface, including areas with and without ecological network projects, and enables linkage of the dataset with other non-spatial data sources for future analyses. To improve future analyses, the dataset contains additional information, such as the area and start year of an ecological network project, as well as the geographical share of ecological network projects in a municipality.