Technically the businesses can be older, but they can't be "US businesses" for longer than the US existed. That doesn't take away from the spirit of your point, though.
According to a quick search into Finnish companies, the currently oldest one (Fiskars, founded in 1649) has survived the transitions from Swedish rule to Russian rule (1809) and to independence (1917). The owners have changed several times. The oldest one that remained in the same family seems to be Frenckells printshop, which survived from 1642 to 2008.