Bobbi on Family Tree Circles

I am researching a Noble Fleming. Date of birth unknown. He married Margaret. Child of Noble and Margaret is Margaret Jane born abt. 1834. She immigrated to America abt. 1856/7 where she met and married James Sanderson also of Northern Ireland. I know this is just sketchy information but I'm not sure where to go from here. I'd like to know where in Northern Ireland they came from.