Prairie-oak butterfly species in the Willamette Valley-Puget Trough-Georgia Basin (WPG) ecosystem have declined dramatically due to widespread habitat degradation and loss of prairie-oak ecosystems in the region. Conservation of prairie-oak butterflies offers unique opportunities and special challenges. Here we provide an overview of butterfly conservation in WPG prairies. We begin with a review of the status of at-risk butterfly species in the region, an introduction to five species that are the focus of current conservation efforts: Fender's blue (Icaricia icarioides fenderi), Taylor's checkerspot (Euphydryas editha taylori), mardon skipper (Polites mardon), island marble (Euchloe ausonides insulanus), and Oregon silverspot (Speyeria zerene hippolyta), and a brief review of 10 additional at-risk butterfly species in the ecoregion. We follow with a discussion of three key threats (habitat loss and fragmentation, invasive species, and lack of appropriate disturbance) and four dominant management approaches (fire, herbicides, mowing, and habitat restoration). We discuss current challenges and emerging issues for these species, and focus on invasive species management, understanding basic biology, conserving multiple species, and adapting to climate change. We highlight several success stories from around the region. We conclude that butterfly biologists and land managers in the WPG are in a unique position to conserve the region's threatened prairie butterflies. Facilitating greater communication across the region through organizations such the Cascadia Prairie-Oak Partnership will assist in recovery of the WPG's threatened, endangered and at-risk butterfly species.