I'm beginning to feel like I'm leading you down dead ends.
But...couldn't resist in telling you my recent find. I seached Google (my most favorite search engine) at http://www.google.com/http://www.google.com/ with the quoted words "Israel Dillon" and came up with (after a few clicks):
106. Israel DILLON was born in 1800 in Franklin, Greene, Pennsylvania. He died in 1854 in Sacramento, Sacramento, California. He was buried in 1854 in Marengo, Iowa, Iowa. He was married to Mary HALL on 30 May 1822 in Millwood, Knox, Ohio.
The only reason why the above caught my eye was because your inquiry also mentioned the town Marengo, Iowa.