County Clare hosts the oldest known evidence of human activity in Ireland. The patella of a bear, which had been  butchered,  was found in the Alice and Gwendoline Cave, in  Clarecastle. It has been dated to 10,000BC.

There was a Neolithic civilization in the Clare area. They left evidence behind in the form of ancient dolmens. The most noted one is known as Poulnabrone dolmen, in the Burren. The remains of the people inside the tomb have been excavated and dated to 3800 BC.

Ptolemy created a map of Ireland in his Geographia with information dating from 100 AD; it is the oldest written account of Ireland that includes geographical features. He identified a tribe in Clare known as the Gangani.

During the Early Middle Ages (500-1,000 AD), the area was part of the Kingdom of Connacht ruled by the Uí Fiachrach Aidhne. In the Middle Ages, it was annexed to the Kingdom of Munster to be settled by the Dalcassians. It was renamed Thomond/North Munster. The most famous leader from there was Brian Boru, High King of Ireland.

For centuries after 1118 the Kingdom of Thomond was ruled by the O'Brien Clan. After the Norman invasion of Ireland in 1169, Thomas de Clare established a short-lived Norman lordship of Thomond. In 1543,

during the Tudor conquest of Ireland, Murrough O'Brien, by surrender and regrant to Henry VIII, became Earl of Thomond within Henry V111s Kingdom of Ireland.

Clare was devastated by the Great Hunger/Famine and the subsequent emigration. The population dropped 70% between 1841 and 1966.

It was in Clare that Daniel O’Connell was elected in 1828 and Eamon De Valera was first elected in 1917.

Peadar Clancy from Cranny was an important leader of the revolution in Ireland. He fought in 1916 and continued fighting until he was brutally murdered by the Black and Tans in Dublin Castle on “Bloody Sunday” 1920.

The more common surnames in County Clare include McMahon,  Keane, McNamara, O'Brien, Moloney, Ryan, Kelly, Mclnerney, O'Connor, Hogan, O'Halloran, Burke, Murphy, Lynch and Walsh.

The O'Loughlins, O'Garbhs, O'Briens, O'Connors, O'Deas, O’Quinns, McMahons and McNamaras were the main Gaelic clans in Clare.

The (GAA) Gaelic Athletic Association was founded in 1884 by Michael Cusack who was born in 1847 in Carron, North Clare.

In 2009 Muhammed Ali visited Ennis, Co. Clare to visit his ancestral home.