Dear Deborah, I am afraid none of my Elsers migrated to Illinois. Since I posted the message, I have learned that my John Kasper Elser immigrated about 1850 from Weurtemberg, Germany. The family lived for several generations in Philadelphia. More recently, some have moved to other eastern states.
Some of the Elsers who came from Russheim in mid-1700's and settled in Lancaster County, Pennsylvania,just outside of Philadelphia had one branch who later moved west to Ohio. My suspician has been that my Elsers were a later wave of this family but there is no evidence to support that. Possibly one of those groups moved fartehr west.