Looking for John Sheridan

Looking for John Sheridan, the following is what I know:

- Death certificate states he was 73 years old at death, 21 Apr 1892, so he was born about 1819/20,

- Death certificate lists parents as Patrick Sheridan and Mary (no maiden name),

- Death certificate states he was in America 36 years so he emigrated about 1856,

- He was married twice, 1st wife was Mary Eslund (from son's death cert, hard to read), 2nd wife Sara/Sarah (no maiden name),

- Son Edward born about 1859 so John & Mary married prior to that. Sara/Sarah shows up in 1880, 1890, and 1900 census.

I checked RootsIreland.ie for a baptism for John and found two with parents names of Patrick & Mary: 6 May 1818, Co. Longford, District of Longford, and 11 Mar 1822, Co. Cavan, District of Cavan. No parish listed for either record.

The Tithe Applotment for Co. Caven lists 20 entries for Pat* Sheridan, and for Co. Longford there are 3 entries for Pat* Sheridan. I can't pick any of these entries since I don't know the parish. And, there are 47 entries in Griffith's Valuation.

So, this is going to be a difficult task without some HELP!!

Thank you for any help!

Allison