About 1902, John T. Roberson started a store about 12 miles southwest of Grants Pass and a couple of miles south of Wilderville, which he began to call Wonder because his neighbors wondered where he would get his customers. The coast railroad was about to be built and perhaps he thought that would help to expand business. In December 1903, the post office was officially named Wonder.

Waters Creek runs into Slate Creek near Wonder. Waters Creek was as far as the tracks of the California and Oregon Coast Railroad ever reached. For a few years the people in Wonder could catch a train and literally, back into Grants Pass. There was no way to turn the engine around, so the train went forward from Grants Pass to Waters Creek and backwards from Waters Creek to Grants Pass. Ah, the wonder of it all.