The Oak Grove town site was first platted in 1890 from the original Creighton and Crow donation land claims (DLCs) of the 1830s and 1840s. Subsequent additions and subdivisions of the Oak Grove plat show clear evidence that the area was marked for investment and growth as a result of the trolley line's introduction early in 1893.
The author of Oregon Geographic Names credits a member of the survey team for suggesting the name Oak Grove, based on an area they came upon for lunch -- "a fine grove of oak trees in the northwest part of the tract."
The town site's post office was opened in 1904. First called the 'Creighton Station' due to duplicate use of the name elsewhere on the trolley line, the postal station name was changed permanently to 'Oak Grove' when the confusion was sorted out and corrected in 1907.