Carson Sink is a playa in the northeastern portion of the Carson Desert that was formerly the terminus of the Carson River. The sink is currently fed by drainage canals of the Truckee-Carson Irrigation District. The southeastern fringe of the sink where the canals enter is a wetland of the Central Basin and Range ecoregion, which is mostly included within the Fallon National Wildlife Refuge and the Stillwater Wildlife Management Area. This area serves as an important stopover for migrating waterfowl. The Sehoo Formation is in the south of the Carson Sink.