Search two online databases: 1) the IFHF's online database at ROOTSIRELAND.IE. It has abt 20 M church, civil, census, etc records for MOST Irish counties. and 2) IRISHGENEALOGY.IE It is smaller and covers a few areas not currently inf the IFHF. Records before 1863 are increasingly sparse - almost non-existant before 1800.
NOTE - Records are still being transcribed into these databases.