Just outside Ballina sits a small megalithic dolmen, three upright stones supporting a heavy capstone, with a fourth stone leaning nearby. The structure is about five feet high and roughly four thousand years old. Local tradition holds that this is the burial place of the Four Maols, four brothers who murdered Ceallach, a seventh-century bishop of Kilmoremoy. The word maol means 'bald' in Irish, possibly because the brothers had tonsures. They were hanged at Ardnaree, the 'hill of executions', which today is a suburb of Ballina across the river. The story is older than the town itself. Ballina as a settled town dates only from around 1375, when an Augustinian friary was founded here, and from 1723 when Lord Tyrawley laid out the formal garrison town that became modern Ballina. The dolmen and the legend are several thousand years older than either.

In August 1798, three French frigates landed about 1,100 soldiers at Killala, fifteen kilometres north of Ballina. The commander, General Jean Humbert, was answering an appeal from the United Irishmen for French military support of the Irish rebellion. Within days the French had taken Ballina without a fight, joined by local Irish rebels armed mostly with pikes. The combined Franco-Irish force then marched south to Castlebar, routed a much larger British garrison there, and briefly proclaimed an Irish Republic. The republic lasted weeks before British reinforcements crushed it. But the moment is permanently fixed in Ballina's memory. The Humbert Memorial Monument was unveiled in 1898 by Maud Gonne MacBride to mark the centenary. It stands today in front of St Muredach's Cathedral, topped by a statue of the Maid of Erin with sword and Irish Wolfhound, a memorial that commemorates the only time French and Irish revolutionaries together drove the British out of an Irish town.

The River Moy flows through the centre of Ballina and out to Killala Bay, and it is, by most measures, the most prolific salmon river in Europe. The fish run upriver from the Atlantic from spring through autumn, and the Ridge Pool right in the middle of town is among the best-known salmon fishing spots in Ireland. The Ballina Salmon Festival happens every July, with a Heritage Day when much of the town centre closes to traffic and stalls take over the streets. The Salmon Weir Bridge, a pedestrian footbridge designed to resemble a fishing rod, opened in 2009 and links the two banks at the Ridge Pool. The whole town is laid out around the river: the two main road bridges, the Lower Bridge from 1835 and the Upper Bridge from 1836, both stone with multiple arches, channel traffic in a one-way loop around the centre. The Belleek Woods on the west bank cover 200 acres, making them one of Europe's largest urban woodlands. The river defines everything.

Mary Bourke was born in Ballina in 1944, the daughter of two doctors. She went to Trinity College Dublin, studied at Harvard Law School, became a barrister and a Senator, and then in 1990 became the first woman ever elected President of Ireland. Her presidency, from 1990 to 1997, fundamentally changed how the Irish presidency worked and how Ireland saw itself. She opened the doors of Áras an Uachtaráin, the presidential residence, to groups long marginalised in Irish life: the gay community, the diaspora, the Travelling community, women's organisations. She kept a symbolic candle burning in the window of the Áras for emigrants. When she left office, she became United Nations High Commissioner for Human Rights, and later a major figure in the global climate justice movement. She still owns property in Ballina. Her family roots run deep into the town, the way nearly everyone's roots in Ballina seem to.

Like much of rural Ireland, Ballina lost its Irish language during the early twentieth century. By the 1926 census, although many adults still spoke Irish as their first language, no children were learning it any more. Today the only Gaeltacht area left in County Mayo, Ceathrú Thaidhg, sits seventy kilometres west. The town survived the Irish War of Independence with its share of violence: the murder of IRA volunteer Michael Tolan in April 1921, his mutilated body discovered in Shraheen bog two months later; the killing of Sergeant Anthony Foody on a road near Bonniconlon in July 1921. The town survived the Civil War, which brought Free State troops into Ballina and burned the Earl of Arran's Castle Gore nearby in September 1922, destroying 350 paintings in a single blaze. The Belleek estate, the Quay, the Crockets Town tenements, all kept turning over their populations through the twentieth century. In November 2024, Ballina completed the redevelopment of its 1742 military barracks into the Ballina Innovation Quarter, with space for up to 200 jobs. The barracks that once held the British garrison who lost the Year of the French is now an office park, which feels, for Ballina, about right.