Legal Question in Family Law in California

Maybe yes, maybe no. Depends on a lot of factors. You don't provide enough information even to begin to evaluate if it might be legal in your situation. Divorced, married, separated? Existing orders? If so what do they say? Etc. There is no yes/no answer.

If there is no specific court order preventing this from happening, then the parent may be able to move. However, they run the risk of the other parent taking action in the court to have the child returned to the home county. Please meet with an experienced family law attorney to explore your legal options.