I had Briggs ancestors in Ireland, too. William Briggs was supposedly from County Clare, moved to Galway City in early 1800s. They were shipwrights. George is one name that appeared later in family.The name Briggs is supp. an English variation on Bridges commonest in West Yorkshire. For NYC research, NYC directories are a good start.There are also state censuses in odd years (1855,e.g.) and odd records like test books of Emigrant Savings Bank that sometimes state where person came from. All available at NY Public Library, but I don't know how to access them long distance.