Lakes in arid and semiarid regions are often found surrounded by paleoshore relics, attesting to a substantially moister condition in the past. The paleolake extent is critical for us to understand the paleo-climatic and paleo-hydrologic environments. Using geospatial information technologies, this letter develops a semiautomated tool for paleolake recovery, PaleoLakeR, which allows efficient paleolake mapping. Paleoshore relics are first identified in high-resolution imagery, and their elevations are determined from digital elevation data. The paleolake extent is then recovered by tracing the contour at the determined paleoshore elevation. With the assistance of PaleoLakeR, the operator only needs to interactively locate paleoshore segments in satellite images, and the tool can automatically determine their elevations, recover the paleolake extent, and compute the water loss due to lake shrinkage. As demonstrated in recovering hundreds of lakes across the Tibetan Plateau, PaleoLakeR is capable of efficiently mapping paleolakes at regional scales.