Leixlip's history has been dictated by its unique location at the confluence of the River Liffey and the Rye Water on the border between the ancient kingdoms of Leinster and Brega. As the Rye flowed mightily beneath the ice face 15,000 years ago, the Liffey found a new course from the Dublin mountains and joined the Rye Water to form the oldest of Ireland's rivers. At Leixlip the waters tumbled down several lesser falls and a grand cataract, a natural course for salmon which glimmered as they swam through the air and water to spawn. With an abundant food source and open fields for crops, Nature gave early man a home, evidence of which is at Cooldrinagh, just off the motorway entrance to Leixlip.

Ancient earthworks including a long mound on an east-west axis is located at Cooldrinagh in the bend of the river as it turns towards Dublin and the sea ten miles downstream. Ancient mysteries abound, waiting to the discovered under the green vista of what is now two golf courses and the newly-acquired public lands of an adjacent demesne which straddle the Liffey.Viking incursions began in 795 A.D. For 300 years these intrepid sailors and warriors terrorised much of Europe and the Middle East, from Baghdad to Iceland. Dublin was a key Viking settlement. At Leixlip the Battle of Confey was fought in 917 A.D. circa. Battles waged back and forth between the natives and the invaders until a comprehensive Irish victory by Brian Boru in 1014 A.D. In addition to their legacy of fighting, trading, and craftsmanship, they left the site of the two rivers with a name, "Lax-hlaup" or "Salmon Leap," the only inland Norse place name.

Two hundred years later the Norman French arrived, descended from Ireland's former marauders, the Vikings. They came at the behest of the English king, Henry II, in 1171 on invitation by the disgraced King of Leinster, Dairmuid Mac Murrough. And through the process of incastellation - the policy of construction, not destruction - subjugated three-fourths of the country in 70 years.

Under Richard, Earl of Pembroke, surnamed Strongbow, the lands of Leixlip were granted to Adam de Hereford where he began construction of Leixlip Castle in 1172. The castle was built as an outpost of The Pale on a rock at the confluence of the two rivers. Henry's son, John, Richard The Lionheart's brother, when Prince and Lord of Ireland, is supposed to have stayed at the castle in 1185. This was the time of The Crusades and the feint outline of a skull and crossbones on the Southeast corner of St. Mary's church nearby bears testimony to the times.

The Norman's built strong stone buildings with wooden roofs which were not immune to warfare and fire. As a military occupation outpost the castle and neighbouring settlement buildings came under attack. St. Mary's was destroyed when the King of Scotland, Robert Bruce, and his brother, Edward, invaded Ireland (1315 - 1318) and attacked Leixlip Castle. For four days the castle withstood the onslaught before the Bruces retreated leaving the church in flames. Only the stout tower survived intact. For 335 years the church remained derelict. The turbulence of the times was reflected politically. Granted to the Eighth Earl of Kildare, taken from the Tenth Earl, the rebel Silken Thomas, and restored to the Eleventh Earl, Leixlip's fortunes were tied to the Norman-Anglo-Irish FitzGeralds. Beginning with Strongbow, who took an Irish wife on the battlefield, the policy of intermarriage between foreigner and native created a new group within society with different allegiances. The FitzGeralds became the Sean Ghalls - the New Irish. Based at Maynooth, the Geraldines of Kildare held the entire county with parts of Meath, Dublin and Carlow, while their castles stretched to the west coast, from the coast of Down to Adare outside Limerick

The tenth Earl of Kildare, Silken Thomas, believed a rumour that his father had died in the tower, the false rumour led to the 20-year-old's rejection of the Sword of State and declaration of war. After an ill-advised campaign he surrendered and after a cruel detention at the Tower of London was hanged, drawn and quartered in 1537 and an Act of Parliament decreed all the lands confiscated. Other members of the family were executed, leaving a lone 12-year-old, Gerald FitzGerald, to be spirited out of the country until his title was "legitimised" by Queen Elizabeth I and a portion of his lands restored in 1554. Sir Nicholas Whyte's family became the occupants of Leixlip Castle in 1569 until Georgian times.

A notable assault on the castle was conducted in the War of The Forties - the 1640's - when Owen Roe O'Neill destroyed the bridge over the Liffey linking Cooldrinagh with Leixlip Castle in 1648. It was O'Neill's brilliance as a commander and strategist which foreshadowed one of Ireland's greatest catastrophes, the emergence of Oliver Cromwell who in eight months created a reputation for cruelty which still stands. The relative calm following Cromwell's departure paved the way for emergence of the Enlightenment, the growth of English wealth, and power which saw Dublin become the second city of the British empire. In 1731 the Irish Parliament published an Act to build a road and construct a bridge over the Liffey. Leixlip Bridge and Toll House were erected in 1734. Travellers were required to pay a toll of a halfpenny. Georgian Society travelled, in season, from throughout the British Isles to view the sight of salmon climbing the cataract. In 1780 visitor Philip Luckcombe recorded the, "It is really a most diverting kind of entertainment to see the many unsuccessful efforts of these large and beautiful fish to gain the tip of the fall before they succeed. Their spring is undoubtedly from the surface. The manner of giving themselves this surprising leap is by bending their tails almost to their heads and by the strong reaction of their tails against the water it is that they spring so much above it".

In 1732 the castle was acquired by William Conolly, nephew of Speaker William Conolly, who inherited Castletown House, the lands of which adjoin the Leixlip demesne to the west. That same year, Dr. Arthur Price, Archbishop of Cashel, bequeathed £100 to his agent, Richard Guinness, and a similar amount to young Arthur Guinness. He invested the money by experimenting with a small brewery on the banks of the Liffey. By 1758 at the age of 34, Guinness required a larger location and decamped to an acre of land at St. James's Gate, Dublin to further his fortunes. The recipe is still made with Kildare water and has evolved into 19 separate recipes to cater for world-wide tastes.

Conolly's legacy included the Palladian architecture of the finest house in Ireland, Castletown. His home was the first Irish house designed by an architect using classical proportions. That architect was Alessandro Galilei. His design served as the model for the White House in the colonies, later to become the United States of America. The Conolly fortune also provided Leixlip with another landmark, the Wonderful Barn. Commissioned by Conolly's widow, Katherine, the conical tower stands 73 feet high and is surmounted by an external spiral stone staircase of 94 steps. It was built in 1743 as a philanthropic gesture to give employment to the poor. The practical purpose was to safeguard the harvest from the marauding O'Tooles and O'Byrnes who scoured the countryside in search of food during the poor Winters of 1739 - 44. A second Conolly project which did not evolve was the creation of a classical thermal spa on land that is now the nature reserve. There the waters bubble from the ground at a constant 75 degrees and drain down to the Rye. The spa was widely used. Louisa Bridge above the spa, was built in 1794, is named after Conolly's wife, Louisa. The Mid-1700's saw the rise of the mill, an iron works, a distillery and linen mill, all industries of the prosperous ascendancy. Cooldrinagh House, Carton House, the Shingled House, and others give testimony to their wealth and power and English connections. The Rye River was disguised to resemble the Thames of London in a landscape attributed to Capability Brown at Carton.

Construction of the Royal Canal began in 1755 after a bitter former director of the Grand Canal competed for a more expensive northerly route to the West from Dublin to the River Shannon. John Binns persuaded the second Duke of Leinster, a trustee of the canal company, to divert the canal southward around his estate at Carton and over the Rye Water, necessitating the construction of an aqueduct 85 feet above the river, 25 feet higher than the famous Clyde navigation in Scotland. The tremendous engineering effort took six years and cost more than £150 million by present standards. The 16 miles of canal works from Dublin to Kilcock took 20 years, time enough for the evolution of the steam engine and doom for canal transport. The canal was sold to the Midland Great Western Railway in 1845 as a quick, ready made route to Mullingar. That same year the director of the Botanic Garden in Dublin noted that the leaves on potato plants in the trial garden had shrivelled and turned black. With a brief account of what he had found in the Dublin Evening Post of 6 September 1845 the Great Famine intervened, destroying the diet for half the population and tearing them from the weeping countryside. As part of the Pale, Leixlip did not suffer to the same extent as the towns and villages to the west with their fields divided and sub-divided.

The Victorian period brought an important development - electricity. Electrification became a major requirement for the fledgling Republic and in 1948 the Electricity Supply Board (ESB) completed the construction of a dam, 24 metres high and 100 metres wide, creating a 100-acre lake, submerging the Salmon Leap but creating 38,000V of electricity for transmission.

Closure (1997 marks the 100th anniversary) and amalgamation of the railways was paralleled by the development of motor transport. These forces began to be felt in the 1970's with the construction of new housing estates in the village, it's major employer a meat-packaging plant, creating a dormitory satellite for Dublin. Consolidation of the meat industry brought closure of the plant and the town's only other major employer, a light bulb factory closed with the advent of cheaper imports.

Government intervention and a new industry, computers, led to the location of the Intel facility. The microprocessor manufacturer has meant 4,000 new jobs and an inward investment of more than £1 billion. Intel has been joined by Hewlett-Packard's ink cartridge facility under the shadow of the Wonderful Barn, creating more than 1,000 additional jobs. Leixlip is now one of the fastest growing towns in Ireland and the largest in Kildare, with a total population estimated at 15,000 and 4,000 households.

These hi-tech industries are creating a new Leixlip, historic developments on historic grounds, surrounded by waters which have seen much human drama, an international perspective on a world no longer divided by hedgerows, race, colour or creed but united in knowledge, brought together through intelligence and information. In Cyberspace. From Leixlip.