I’ve discovered many McMahons in my family who emigrated to Pennsylvania in the mid-19th century – mainly to become miners. Further research has shown that members of the McMahon family were arriving in Philadelphia in the very early 1800s.

On 6 July 1802, Denis and Henry McMahon left on a ship called the Mohawk bound for Philadelphia. It sailed from the city of Derry – or Londonderry if you prefer – in British-ruled Ireland and the ship’s master was a certain John Barry. Unsurprisingly the two McMahons were booked into ‘steerage’ – the lowest class.

The journey would have taken six weeks in favourable weather but if it was stormy, the horrific experience could have lasted up to fourteen weeks. Three months at sea in dreadful conditions. But they were leaving an Ireland that had gone through huge political upheavals and economic deprivation in the years previously. For Irish Catholics like the McMahon family things had been grim for over a hundred years with the Penal Laws that forced them to recognise the British state backed Church of Ireland.

In 1801, the Act of Union was passed and the Irish Parliament in Dublin was wound up. From now on, Ireland would be ruled directly from London. There were guaranteed seats for Ireland in the House of Commons and House of Lords…..so long as you were an Anglican (Church of England or Church of Ireland). And the country became known as the United Kingdom for the first time.

Forty years later, Ireland would be hit by an appalling and probably preventable famine caused by a potato blight. The far-off legislators in London were blamed for neglect as people succumbed to starvation. Now I know many in the McMahon family – normally a couple of siblings in each generation – boarded a ship for America. At least two siblings of my great great grandfather did exactly that while others went to the industrial heartlands of Scotland seeking work.

But what I’ve found is that the McMahon brain drain was underway decades earlier. And Philadelphia was where they began to flood in. For example, Anne McMahon, aged 47, left Liverpool for Philadelphia on 17 September 1821. Liverpool was a port of exit for immigrants from all over Europe bound for the eastern seaboard of the United States.

The Irish didn’t get the fondest of receptions on other other side and there were anti-Irish riots in Philadelphia. But over time, Irish Americans took over districts built years before by the rich and wealthy. Big old houses got divided up into tenements. Though those Irish people in turn made their money and some even moved into the upper ranks of society.