Habitat loss and its effects on populations of vulnerable species is among the most urgent problems in conservation ecology. It is critical that managers and scientists have effective tools to evaluate the effects of landuse and climate change on the extent and connectivity of populations. To address this need, we introduce UNIversal CORridor network simulator (UNICOR), a species connectivity and corridor identification tool. UNICOR applies Dijkstra's shortest path algorithm to individual-based simulations. Outputs can be used to designate movement corridors, identify isolated populations, quantify effects of climate and management changes on population connectivity and prioritize conservation plans to maintain population connectivity. The key features include a driver-module framework, connectivity mapping with thresholding and buffering, and calculation of graph theory metrics. Through parallel-processing, computational efficiency is greatly improved, allowing analyses of large extents (grid dimensions of thousands) and large populations (individuals in the thousands).