I'm an Ayd descendant here in MN. The Aydts in Hamilton Co., Il immigrated from Ersingen and Bilfingen, Amt Pforzheim, Kreis Karlsruhe, Baden. There were lots of Aydts along with many others from their town who moved there. Most seemed to be interrelated. My g-g-grandparents marrieddown there & they were fourth cousins twice over! In the 1850s, many of these people in IL moved to St. Paul & St. Michael, MN. Ayd Mill Road in St. Paul is named for the mill built there by John Kajetan Aÿd. The name was spelled with a German umlaut over the "y", making it like a long "i". I have read that in MN, three Aÿdt brothers, Edward, Theodore & Kajetan, spelled their surnames slightly differently so you can tell which branch a descendant is from: Ayde, Aydt or Ayd, respectively, but don't count on correct spellings in the census! In Germany, you most commonly see Aÿdt but the "d" at the end would be pronounced like a "t" in any case.