Uí Maine was the name of a kingdom situated in south Connacht, consisting of all of County Galway east of Athenry, all of southern and central County Roscommon. In prehistory it was believed to have spanned the River Shannon, and in the 8th century even briefly extended its dominion west to Galway Bay. It existed as an independent kingdom from prehistoric times, and as a subject kingdom up to the end of the medieval era. The acknowledged senior branch of the Ó Ceallaigh (O'Kelly) Uí Maine is the O'Kelly de Gallagh and Tycooly (see Irish nobility and Chief of the Name), and are Counts of the Holy Roman Empire. Other branches include: O'Kelly of Aughrim, O'Kelly of Mullaghmore, O'Kelly of Clondoyle, O'Kelly de Galway, Ó Ceallaigh Iarthar Chláir, O'Kelly of Gurtray, O'Kelly of Screen, and O'Kelly Farrell.

Semi-historic kings

All dates approximate.

Early historic kings

High medieval kings

Post-Norman kings

Kings of the Clanricarde era

Early modern chiefs

Chiefs of the Name