My Thomas Dundon came 1819 to Portage Co (Ohio Western Reserve ) and married 1820, died by 1830. I don't know if he is related to you r's but he did have a child (we suspect) named James too. I never knew of this James, but another researcher thinks he is my Thomas' as he was the only Dundon in Portage Co in early times. And his James was born in Portage Co.
I don't know where my Thomas Dundon came from except he wasn't naturalized and his son's bio says he was not naturalized. Oh he was Irish.