Most of the famous old American brands are now owned by other companies.
Hamilton is now owned by the Swatch group, still makes mechanicals.
Elgin is owned by MZ Berger, makes cheap quartz watches, mostly with Chinese manufacture.
Gruen was an American brand using mostly Swiss parts, is now owned by MZ Berger, mostly cheap quartz. Recently experimented with a Swiss Automatic, but failed.
Waltham is now two separate brands. MZ Berger owns the rights to the name in North America, Waltham International SA owns the brand in the rest of the world, concentrating on Japan. Waltham International was established by the original American Waltham.
Timex is still basically the original company, Norwegian ownership, US headquarters, worldwide production.
Bulova has had several ownership changes, but is still around, although with no US manufacturing.
Accutron--Bulova moved the Accutron name to standard quartz watches, and now makes mechanical Accutrons.