http://homepages.rootsweb.ancestry.com/~aherns/ahnat.htm#Bostonhttp://homepages.rootsweb.ancestry.com/~aherns/ahnat.htm#Boston lists several Patricks who became citizens in Boston. One Patrick O'Hearn was born May 4, 1845 and naturalized April 27, 1885. And there's a Patrick Ahearn born March 3, 1844 who was naturalized November 3, 1876. You need to see if he is in the 1900 census and, if so, whether he is a citizen. If he was naturalized in Boston, or in a US District or Circuit Court in any New England state the original naturalization record should be at the National Archives regional branch in Waltham, Mass.