1670s, alteration (influenced by wood (n.)) of Cree (Algonquian) otchek or Ojibwa otchig, "marten," the name subsequently transferred to the groundhog.
Entries linking to woodchuck
wood n.
Old English wudu, earlier widu "tree, trees collectively, forest, grove; the substance of which trees are made," from Proto-Germanic *widu- (source also of Old Norse viðr, Danish and Swedish ved "tree, wood," Old High German witu "wood"), from PIE *widhu- "tree, wood" (source also of Welsh gwydd "trees," Gaelic fiodh- "wood, timber," Old Irish fid "tree, wood"). Out of the woods "safe" is from 1792.
ground-hog n.
also groundhog, "American marmot," 1784, from ground (n.) + hog (n.). Also known colloquially as a whistlepig, woodchuck, and compare aardvark. Ground Hog Day as a weather forecasting event is first recorded 1869, in an Ohio newspaper article that calls it "old tradition;" the custom though not the name, attested from 1850s. Similar superstitions are widespread; Webster ("The White Devil") refers to one from Elizabethan London:
Let all that belong to great men remember th' old wives'
tradition, to be like the lions i'th' Tower on Candlemasday ;
to mourn if the sun shine, for fear of the pitiful remainder