The first real signs of settlement at Athlone grew up in Anglo-Norman times around the castle which was built for King John of England by his Irish justiciar Bishop John De Gray of Norwich.  Though not the first castle to be built at Athlone this castle has endured like no other.  Looking at it today it still incorporates elements of the castle of 1210 together with various additions and alterations which were made in response to advances in warfare.  It has many of the characteristics of a Napoleonic fortification as it was remodelled during that period to defend the crossing point of the Shannon.

Over the centuries it has been the nucleus of the Anglo-Norman settlement; a stronghold of the rival local families the Dillons and the O’Kelly’s; the seat of the Court of Claims; the residence of the President of Connaught and the Jacobite stronghold during the sieges of Athlone.  After the Siege of Athlone it became incorporated into the new military barrack complex.  It remained a stronghold of the garrison for almost three hundred years.

In 1922 when the Free State troops took over the Barracks from their British counterparts, they proudly flew the tricolour from a temporary flagpole much to the delight of the majority of townspeople.

In 1967 the Old Athlone Society established a museum in the castle with a range of exhibits relating to Athlone and its environs and also to folk-life in the district.  Two years later when the military left the castle it was handed over to the Office of Public Works and the central keep became a National Monument.

In 1991 to mark the Tercentenary of the Siege of Athlone the castle became the foremost visitor attraction in Athlone.  Athlone Town Council (then Athlone UDC) made a major investment in the castle creating a multi-faceted Visitor Centre as it approached its 800th Anniversary in 2010. A total of €4.3million euro was invested in the new facility by Fáilte Ireland and Athlone Town Council and was officially opened by the then Minister of State for Tourism and Sport, Michael Ring T.D. on Tuesday 26th February 2012.
Athlone Castle Visitor Centre is now a modern, engaging, fun and unique family attraction which harnesses most significant architectural features, such as the keep, to act as a dramatic backdrop to its diverse and fascinating story.
It houses eight individual exhibition spaces, each depicting a different aspect of life in Athlone, the Castle and the periods both before and after the famous Siege. Fun, hands-on interactives, touchable objects and educational narratives immerse visitors in the drama, tragedy and spectacle of Athlone’s diverse and fascinating story. 3D maps, audio-visual installations, illustrations and artefacts bring the stories and characters of Athlone to life and The Great Siege of Athlone is dramatically recreated in a 360-degree cinematic experience in the Keep of the castle.

As part of Westmeath County Council’s commemoration of Ireland’s world-renowned tenor, John Count McCormack, a new exhibition dedicated to the celebrated singer was opened at Athlone Castle in October 2014.

Athlone Castle Visitor Centre will continue to be refreshed as time goes by, but the castles’ origins and story will remain cast in stone and intrinsic to the history of Athlone.

In 1210, Bishop John de Gray of Norwich, a close confidante of King John spent £129 pounds on the building of Athlone Castle on the site of the Norman motte, first constructed in 1129. This stone building, polygonal in shape lasted for one year before its collapse in 1211, killing 8 Normans as well as Richard Tuit, the man who constructed the stone tower.

From 1569-1672, Athlone Castle was the headquarters of the Presidency of Connacht and a residential palace was built in the courtyard of the Castle. The establishment of the Connacht Presidency in 1569 brought with it the division of Connacht into counties but county administration was not achieved until 1585.

The Connaught Tower was a tower house structure built in the 16th Century as a defensive tower within the outer works of Athlone Castle. It survived until the Williamite bombardment of the town during The Great Siege of Athlone in 1691. The structure, according to excavation work carried out, is said to have occupied the site of the former Father Matthew Temperance Hall. This building is now the Luan Gallery.