| Hemigrapsus sanguineus, Hemigrapsus oregonensis, Purple shore crab, Hemigrapsus takanoi|
Hemigrapsus is a genus of varunid crabs comprising thirteen species found almost exclusively in the Pacific Ocean.
The natural range of the genus is restricted to the Pacific Ocean, except for Hemigrapsus affinis which lives along the Atlantic coasts of South America, from Cape São Roque (Rio Grande do Norte state, Brazil) to the San Matías Gulf, (Patagonia, Argentina). H. estellinensis is almost certainly extinct, but was endemic to a hypersaline spring in the Texas Panhandle, 500 miles (800 km) from the sea. Populations of Hemigrapsus sanguineus have been introduced from the species' native range in East Asia to several places, and now range from Portland, Maine to North Carolina, and along the English Channel; H. takanoi has been introduced to western Europe, and now extends from northern Spain to the English Channel.
Fifteen species are currently recognised: