In 1129, to protect the bridge, the High King Turloch Mór Ó Conor constructed a fort on the river's west bank, within Athlone.

On a number of occasions both the fort and bridge were subject to attacks, and towards the end of the 12th century the Anglo-Normans constructed a motte-and-bailey fortification there.

The 12-sided donjon, or tower, dates from this time; however, the rest of the original castle was largely destroyed during the 1691 Siege of Athlone and subsequently rebuilt and enlarged.

[9] Throughout the wars that wracked Ireland in the 17th century, Athlone contained the vital, main bridge over the River Shannon into Connacht.

In the Irish phase of the conflict (the Williamite War in Ireland of 1688–1691), Athlone was one of the Jacobite strongholds that defended the river-crossings into the Jacobite-held Province of Connacht following the Battle of the Boyne on 1 July 1690.

That same year, Colonel Richard Grace's Jacobite forces in Athlone repelled an attack by 10,000 men led by Commander Douglas.

In the following year's campaign, the Siege of Athlone saw a further assault by a larger allied force, during which the invading troops of King William and Queen Mary eventually overran the entire city.

The defenders were forced to flee further west, toward the River Suck, at such speed that eyewitness accounts record that they "flung their cannons into the morass" as they fled.

The account was penned by the victorious commanding officer from the Republic of the Seven United Netherlands, general lieutenant Godard van Reede, in letters written to his family in mainland Europe.

In terms of ecclesiastical boundaries, the eastern part of the town is in the Roman Catholic Diocese of Ardagh and Clonmacnoise and the parish of St Mary's.

However, seven townlands, or sections of the town, lie west of the Shannon: Athlone and Big Meadow, Bellaugh, Bogganfin, Canal and Banks, Doovoge, part of Monksland, and Ranelagh.

[14] In terms of ecclesiastical boundaries, the townlands west of the Shannon are part of the Roman Catholic Diocese of Elphin and the parish of Saints Peter and Paul.

[citation needed] Lough Ree, the largest lake on the Shannon, is a short distance upstream from Athlone, and many boat companies are based out of the town.

[citation needed] Athlone railway station opened on 3 October 1859,[17] with Irish Rail services travelling eastwards to Portarlington, Kildare and Dublin Heuston and westwards to the Westport/Ballina lines as well as to Athenry, Oranmore and Galway.

[18] Bus Éireann services between Dublin and Belfast, Cork and Limerick were also cut following a "viability review" of 18 routes in September 2020.

A number of national secondary roads connect Athlone with other towns and regions, namely the N55 to Ballymahon and Cavan, the N61 to Roscommon and the N62 to Birr, Roscrea, and Southern Ireland.

The festival is supported by a number of "fringe" events that include street theatre, art exhibitions, workshops and activities for young people.

[citation needed] Athlone Literary Festival is an annual event which began in 1999, originally as a weekend celebration of the life and works of John Broderick, but which now features a great variety of speakers and debaters.

[citation needed] The tenor John McCormack was born in Athlone and, for many years, an annual festival was held in the town to celebrate his life.

[28] American crime writer James M. Cain refers to Athlone in his 1937 book, Serenade, in a passage where two characters discuss tenor John McCormack: "--There's the language he was born to.

[29] The Irish poet Aubrey Thomas de Vere wrote a poem The Ballad of Athlone which is an account of an incident in the 1691 siege.

Sean's Bar, located on the west bank of the river, was certified by the Guinness Book of World Records as the oldest pub in Ireland.

Baysports, a boat training and watersports centre with the world's largest floating inflatable water slide,[citation needed] is located on the outskirts of the town at Hodson Bay.

[citation needed] Examples of public art and sculpture in Athlone include the IRA Memorial which was erected near the corner of Church Street and Custume Place in the early 1950s.

[40][41] The limestone statue consists of a life-sized male figure, dressed in a typical IRA uniform from the period,[38] and was created by Dublin-based sculptor Desmond Broe.

[43][44] A figurative statue, representing the "contributions the Marist Brothers have made to the town of Athlone",[45] was unveiled on St. Mary's Square in 2012.

In June 2010, Taoiseach Brian Cowen announced his support of a proposed European and Chinese training hub in Athlone.

Moydrum was also the location of Ireland's short-lived Shortwave international radio service, which was closed down in 1948 due to lack of money.

[67][68] Local newspapers include the Westmeath Independent located on Sean Costello Street which was established in 1846 and the Athlone Topic.

[71] The stadium hosts the annual AIT Grand Prix event, broadcast by TG4 in Ireland and internationally via Vinco and Runnerspace.