George crossed the plains with his mother, Elizabeth Bowring Oglesby. From George's obituary, it appears that he came to the United States on the ship Horizon when he was five years old. The ship manifest lists a five-year-old boy named Robert N. Bowring traveling with Elizabeth and her husband William. It does not include the George's name. It is likely that Robert and George are the same person.
According to Elizabeth's probate records, he called her his "step-mother---my aunt" and reported that Elizbeth had raised him since he was six months old.