We created the first detailed map of retrogressive thaw slump (RTS) landforms across a large area of the West Siberian Arctic. RTSs are key features of abrupt permafrost thaw accelerated by climate change. Using satellite images and field data, we identified and classified over 6000 RTSs. This dataset helps scientists better understand how warming is changing Arctic landscapes and provides a trusted reference for training artificial intelligence to detect these landforms in the future.