Chaco marsh rat
Holochilus chacarius
- Least concern
- Card rarity: Common
- Mammals

Holochilus chacarius, also known as the Chacoan marsh rat or Chaco marsh rat, is a semiaquatic species of rodent in the family Cricetidae. It is found in Argentina and Paraguay within the Gran Chaco.
Classification
- Class
- Mammalia
- Order
- Rodentia
- Family
- Cricetidae
- Genus
- Holochilus