The kingdom represented the core homeland of the Connachta's Uí Briúin Seóla kindred and although they ruled, there were smaller groups of other Gaels in the area, such as the Delbhna Tir Dha Locha and the Conmhaícne Mara.

Galway's Norman oligarchy later achieved a quasi-independent status to carry out its trade, but there always lingered the threat of it being reconquered by the Gaelic Ó Flaithbheartaigh, particularly during the 14th and 15th centuries.

This clan had originated as part of the Connachta, specifically the Uí Briúin Seóla kindred and were also known as the Muintir Murchada, claiming descent from Murchadh mac Maenach.

The Ó Conchobhair got the better of the conflict and the subsequent descendants of Amhalgaidh mac Cathal gradually began relocating west of Lough Corrib into Iar Connacht (what is today more commonly known as Connemara).

Prior to the aforementioned events, the lands to the West of Lough Corrib were under the Delbhna Tir Dha Locha and the Conmhaícne Mara; these two groups were distinct from the Connachta in general.

Iar Connacht suffered several significant invasions from Munster during this time, including during the reign of Conchobhar Ua Flaithbheartaigh who was the first Governor of Dun Gallimhe (Galway) and died there in 1132 defending the fort from Cormac Mac Carthaigh.

However, while staying at Cong, the ambitious Norman wanted a heavy payment for his services and frustrated, entered into a pact of conspiracy with the sons of Ruadhri Ua Flaithbertaigh to kill Cathal Crobhdearg.

Although technically brought under the aegis of the British Empire's Kingdom of Ireland toward the end of the 16th century, the indigenous Gaelic culture and language of Iar Connacht would continue on for a long time after.