Looking for a connection between this family in 1871 Canada Census of Montague, Lanark South, Ontario:

Patrick Brennan abt 1800 Ireland
Catherine Brennan abt 1811 Ireland
Patrick Brennan abt 1845 Ontario
Michael Brennan abt 1852 Ontario
Margaret Brennan abt 1853 Ontario
William Brennan abt 1855 Ontario
Catherine Brennan abt 1856 Ontario
Bridget Brennan abt 1857 Ontario
Thomas Brennan abt 1859 Ontario
Nicholas Brennan abt 1861 Ontario
Simon Brennan abt 1863 Ontario
Joseph Brennan abt 1867 Ontario

and this family in the 1880 census of Syracuse, New York:

1880 Census
Syracuse, Onondaga, New York

Patrick Brennan abt 1822 Ireland Self (Head)
Anna Brennan abt 1828 Ireland Wife
James Brennan abt 1863 New York Son
Nellie Brennan abt 1860 New York Daughter
Nicholas Brennan abt 1867 New York Son

Does this ring a bell with anyone?