Hello Viola,
There's not an 1891 Census but there is on for 1901.
There are three items required which should assist in conducting a successful search for Irish ancestors ...
1. Denomination
2. Parish
3. Townland
If you have these details you may be able to trace the Church that the family attended and have a look at those records.
If the family were tenants on an estate then they may be mentioned in Estate Records as well as Church Records. Some of these records give a reasonable amount of information about tenants.
Christopher