The California Department of Fish and game says biologists on Thursday tracked the wolf's position to a few miles south of the state line in Siskiyou County.
A global positioning system collar was placed on the wolf in February. Since then, the 2½-year-old male has wandered more than 300 miles. The GPS data put the wolf in California as of Wednesday.
Officials say they're only providing general information about the wolf's location, since gray wolves in California are designated a federally endangered species.
The last confirmed wild gray wolf in California was killed in 1924.