No. 18: Brookfield.The town of Brookfield has the 18th largest percentage of resident claiming an Irish ancestry in Southwestern Connecticut, at 19.2 percent. Laurie Boxer, of Brookfield, and her Irish wolfhound, Fergus O'Boxer, march in the Ancient Order of the Hibernian's St. Patrick's Day parade in Danbury, Sunday, March 20, 2011.