Genealogists have always concluded that the last name Zumbrun or Zumbrum is a shortening of the Swiss name Zumbrunnen. (As a general rule of thumb, Germanic surnames beginning with Ze, Zem, Zum, Zur are characteristically from Central Switzerland, though there are of course exceptions).
Heinrich, the first Zumbrun in America, was married in a Rhine Valley town called Schwegenheim and although many genealogies say Heinrich was born in Switzerland[1], he was originally from near the town of Crailsheim, in Baden-Wurttemberg.
The Zumbrunnen family in Crailsheim was very small, however, and likely originated in Switzerland.
This is a quick overview of several branches of the Zumbrunnen family in Switzerland from which Heinrich could have descended, as well as a few minor ones that don’t seem to be likely candidates for our direct ancestry.