Long Island, NY Montgomerys

I'm looking for descendants of my greatgrandfather Michael Montgomery and his wife Elizabeth "Bessie" or "Betsy" Heaney who may know from where in Ireland he came. They were both from Ireland and he arrived in New York City in 1848. I found a Michael Montgomery living with a Thomas & Bridget Montgomery (possible brother) living in Kings County in 1850.On all subsequent censuses Michael and his family was living in Greenport, (Suffolk County)Long Island.His children were Lizzie,William H (my grandfather),James, Mary, Richard, Paul, John & George (twins), Ellen and Agnes.Thanks for your time and attention.