Oldest US City - Oldest US Company?

I just returned from a trip to Florida which included an interesting day in St. Augustine. Most people have heard St. Augustine's claims to being the oldest city in the U.S. but how many know what the oldest company is in the U.S.? It could be the King Arthur Flour Company, established in Boston in 1790 and now an employee-owned company out of Vermont. Or - depending on how one counts - it could be Ziljian (the musical cymbal company) which was established by Avedis Ziljian in 1623 in Constantinople and moved to the U.S. by Avedis III in 1929. Run by the 15th generation of Ziljian heirs, it is generally considered the oldest family-owned business in the U.S. I'd love to hear from people who know of other candidates for oldest U.S. company!