Sky Island grasslands of central and southern Arizona, southern New Mexico and northern Mexico form the “grassland seas” that surround small forested mountain ranges in the borderlands. Their unique biogeographical setting and the ecological gradients associated with “Sky Island mountains” add tremendous floral and faunal diversity to these grasslands and the region as a whole. Sky Island grasslands have undergone dramatic vegetation changes over the last 130 years including encroachment by shrubs, loss of perennial grass cover and spread of non-native species. Changes in grassland composition and structure have not occurred uniformly across the region and they are dynamic and ongoing. In 2009, The National Fish and Wildlife Foundation (NFWF) launched its Sky Island Grassland Initiative, a 10-year plan to protect and restore grasslands and embedded wetland and riparian habitats in the Sky Island region. The objective of this assessment is to identify a network of priority grassland landscapes where investment by the Foundation and others will yield the greatest returns in terms of restoring grassland health and recovering target wildlife species across the region.