Here he is in the 1900 NY Westchester Co Mt Pleasant tsp census: Heslin Michael head Aug 1855 44 married 19 yrs NJ IRE IRE blacksmith Heslin Margaret wife Jan 1859 41 married 19 yrs 7 born 6 living NJ IRE IRE Heslin John son Jul 1882 17 NJ NJ NJ Heslin Michael son Feb 1884 16 NJ NJ NJ Heslin Catherine dau Oct 1885 14 NY NJ NJ Heslin Mary Ellen dau Sep 1889 10 NY NJ NJ Heslin Bernardine dau Nov 1895 4 NY NJ NJ Heslin Lawrence son Sep 1897 2 NY NJ NJ
1870 NH Morris Co Rockaway tsp this may be his family: Heslin Michael 45 miner IRE Heslin Michael 14 minor NJ Heslin Lawrence 12 NJ
1860 NJ Morris Rockaway Micheal(misspelled on census) Heslin 41 miner IRE Mary Heslin 35 IRE James Heslin 11 NJ Rosanna Heslin 8 NJ Micheal Heslin 4NJ Lawrence Heslin 2 NJ
These are not my Heslins. Good luck. I hope this helps.