Cormac Cas was King of Thomond around the fifth century and he spawned a tribal grouping known as the Dál gCais or Dalcassians which dominated Munster until the final suppression of the old Gaelic order in the seventeenth century. Twenty-three generations later and in direct descent from Cas we find Cumara, Chief of Maghadhair in county Clare. Cumara is a contracted form of Conmara - hound of the sea. His son, Domhnall, who died in 1099, adopted the surname Mac Conmara, or son of Cumara, thus becoming the very first MacNamara. The name has survived relatively unmodified as MacConmara in Irish and Mac (or Mc) Namara in English, to this day.
The sept of MacNamara was, after the O'Briens, the most important and powerful of the Dalcassians of Thomond. They were hereditary marshals to the O'Briens and had the privilege of inaugurating their chief who was, of course, often a king. There was frequent intermarriage between these two strong families. The sept was originally confined to a small territory, but by the end of the eleventh century they had become lords of Clancullen (which comprises a great part of East Clare) and they are so described by the Four Masters many times at various dates between 1099 and 1600. The sept in due course became two - the chief of West Clancullen (barony of Bunratty) being MacNamara Fyne (i.e. fionn, fair), and the chief of East Clancullen (baronies of Upper and Lower Tulla) MacNamara Reagh (i.e. riabhach, swarthy or grizzled). They earned a reputation as builders and are recorded as having built forty-two castles, fifteen fortresses and several friaries. Macmiccon MacNamara Fionn received a papal bull authorising him to install Friars Minor in Quin Abbey, near Ennis, which he built in 1402. Many of the family lie buried in the shadow of the now roofless abbey.
Like their ancient fortresses, the MacNamara seats are all in County Clare. From the woods around Cratloe Castle, built in 1610, came the oaks for London's old Westminster Hall and the royal palace in Amsterdam. They were to a great extent dispossessed in the Cromwellian debacle, but one family, resident until quite lately at Ennistymon, became Protestants and were extensive landlords up till the Land Act of 1903.
The history of Clare is full of the name MacNamara. Half a century before America was discovered, John Macmiccon H MacNamara, Lord of Clancullen and High Chieftain of the Dalcassians, completed the building of Bunratty Castle begun by his father, Sioda, and planned his dream castle at Knappogue.

KNAPPOGUE CASTLE derives its name from "Caislean na Cnapoige", the castle of the place abounding in little hills.  The castle was built by Sean Mac Con, the son of Sioda MacNamara, in 1467.  This was the man who built the great transept of Quin Abbey and completed the construction of Bunratty Castle which his father Sioda had started.  The Four Masters referred to him as "the chief protector of the men of Ireland and renowned for his hospitality".   Knappogue became a Cromwellian garrison during that era as the MacNamaras had supported the royalist cause.  Arthur Smith was granted tenancy of Knappogue by the Cromwellians and occupied the building from 1659 to 1661.  After the restoration of the English monarchy, the MacNamaras regained it. 
Francis MacNamara sold it to the Scott family in 1800.  They spent a considerable amount of money renovating it. Theobold Fitzwalter Butler, 14th Baron Dunboyne, bought it in 1855 and turned it into the new family seat of the Dunboyne family.  They continued the restoration work started by the Scotts.  They added a drawing-room, the long room and a west wing, which included the clock tower and the gateway. During the Troubles the Clare County Council met here, guarded by the East Clare Flying Column of the I.R.A., whose commanding officer, General Michael Brennan, used this historic building as his headquarters. 
In 1927 the Knappogue demesne was purchased by the Land Commission and the castle became the possession of the Quinn family.  Mark Edwin Andrews of Houston, Texas, former Assistant Secretary of the United States Navy, bought it in 1966.  With his wife Lavonne, a prominent architect in the U.S., and in co-operation with the Shannon Free Airport Development Company and Bord Failte Eireann, he carried out an extensive restoration before leasing part of the castle to the Irish Government as a cultural and tourist amenity.  There was merely a nominal rent.  The castle is now a medieval banquet venue and guided tours are arranged daily during the tourist season.