| Named By: | Joseph Leidy in 1869 | 
| Time Period: | Late Oligocene to Early Miocene | 
| Location: | USA, Nebraska, Oregon, South Dakota and Wyoming | 
| Size: | About 25 - 30 centimetres long | 
| Diet: | Herbivore | 
| Fossil(s): | Multiple individuals | 
| Classification: | | Chordata | Mammalia | Rodentia | Castoridae | Palaeocastorinae | | 
| Also known as: | | Capacikala sciuroides | Steneofiber nebrascensis | Steneofiber peninsulatus | Steneofiber sciuroides | | 
Palaeocastor ('prehistoric beaver') is an extinct genus of beavers that lived in the North American Badlands during the late Oligocene period.