Geography first. County Limerick sits in the province of Munster, in Ireland's Mid-West, bordered by Kerry to the west, Clare to the north, Tipperary to the east, and Cork to the south. The River Shannon - the longest river in Ireland - runs through Limerick city and widens immediately into the Shannon Estuary, which sweeps the county's northern border on its way to the Atlantic. The estuary is shallow, so the county's important port is several kilometres downstream at Foynes, where flying boats once landed. Smaller rivers - the Mulcair, the Loobagh, the Maigue, the Camogue, the Morning Star, the Deel, the Feale - all drain into the Shannon system. The land between the rivers is mostly flat limestone plain, broken by hill country where it isn't. Galtymore, on the Tipperary border, rises to 919 metres - the highest peak in Limerick and the third-highest county summit in Ireland.

At Lough Gur, southeast of Limerick city, archaeologists have found evidence of continuous human occupation going back 5,000 years. The Grange Stone Circle nearby is the largest stone circle in Ireland - 113 stones, raised about 2200 BCE, still standing in a field where the dairy cattle graze. Around 400 BCE the Celts arrived and divided the land into small kingdoms called túatha. From the fourth century to the eleventh, much of what is now County Limerick was the Uí Fidgenti kingdom, with their capital at Dún Eochair near modern Bruree. Christianity came with St Patrick in the fifth century, who according to the old annals quarrelled with the chief of the Uí Fidgenti over stolen horses, then made peace with the chief's brother. Monasteries followed - Mungret, Ardpatrick, Kileedy. From one of them, or near it, came the Ardagh Chalice, a gold-and-silver communion cup of the eighth or ninth century. It was found by a farmer's spade in a west Limerick fort in 1868.

The Vikings founded Limerick city around 922, on an island in the Shannon. The O'Briens of Dál gCais drove them out, then dominated the region until the Norman invasion. In 1210 the Anglo-Norman crown formally established the County of Limerick and granted the lands of the old Uí Fidgenti to the FitzGerald dynasty. For four hundred years the FitzGeralds ruled, becoming, as the saying goes, more Irish than the Irish themselves - until the Tudor crown decided that was the problem. The Desmond Rebellions of the late sixteenth century laid waste to Munster. The Cromwellian siege of 1650-51 took twelve months to break the city. Two further sieges followed during the Williamite War of 1689-91. The second of those sieges produced General Patrick Sarsfield's famous raid on the Williamite siege train at Ballyneety, the Treaty of Limerick, and the city's enduring nickname - the City of the Broken Treaty, after the English failed to honour the terms.

In the eighteenth and nineteenth centuries, the Catholic majority of County Limerick lived under Penal Law oppression and rural poverty. The famine of the 1840s emptied villages and accelerated the decline of Irish as a daily language. But in towns along the River Maigue - Croom, Bruree - a group of Gaelic poets calling themselves the Maigue Poets kept the older tradition alive. They wrote in Irish, in tight metrical forms, and they gathered in public houses to recite verse and drink. Their connection to the English verse form called the limerick is real but obscure. The five-line AABBA jingle was already a parlour game in English by the eighteenth century, and its refrain - 'Will you come up to Limerick?' - may reference the city, the county, or these specific poets. The Maigue tradition, in any case, is older and graver than the comic verse that took its name.

After Irish independence the county lived through its own Civil War in 1922 - the Battle of Kilmallock saw some of the war's hardest line fighting. In the twentieth century, Limerick became known for its dairy farming, its rugby clubs (Munster Rugby plays at Thomond Park, and the city alone hosts five top-flight clubs), and its hurling team, which has won the All-Ireland Senior Hurling Championship twelve times - most recently in 2023. The Cranberries came from here. So did Richard Harris, the comedians the Rubberbandits, and Frank McCourt, whose memoir Angela's Ashes made the city's mid-twentieth-century poverty famous around the world. In 2014 Limerick was Ireland's inaugural National City of Culture. The county's population at the 2022 census was 209,536; nearly half of them live in Limerick city itself. The bowl of green farmland that was the Uí Fidgenti's kingdom is still, mostly, a bowl of green farmland.