Bad communications and a lack of private capital prevented fast progress until the 1820s when the potato crop failed in 1821–22 and D'Arcy petitioned the government in Dublin for assistance.

By that time, Clifden had grown from virtually nothing to a town of 185 dwellings, most of them three-floored, two churches, two hotels, three schools, a police barracks, courthouse, a gaol, a distillery and 23 pubs.

[6] In 1843, Daniel O'Connell held a 'Monster Meeting' at Clifden, attended by a crowd reportedly numbering 100,000, at which he spoke on repeal of the Act of Union.

Large numbers of people died, as government help proved insufficient to deal with starvation, scurvy and other diseases.

On 18 November 1850, Hyacinth D'Arcy put up his estates for sale and most of them were purchased by Charles and Thomas Eyre of Somerset.

[9] Clifden gained prominence after 1905 when Guglielmo Marconi decided to build his first high power transatlantic long wave wireless telegraphy station four miles (6 km) south of the town to minimize the distance to its sister station in Glace Bay, Nova Scotia.

At peak times, up to 200 people were employed by the Clifden wireless station, among them Jack Phillips, who later perished as Chief Radio Operator on the Titanic.

When Captain Alcock spotted the green bog he thought it was a meadow where he could safely land his Vickers Vimy biplane.

[11] Later that day, British paramilitaries from the Auxiliary Division opened fire during what was intended to be a routine search for IRA suspects during a Gaelic football match at Croke Park, killing twelve and injuring sixty.

[11] Thomas Whelan, born in 1899 in Clifden, was arrested and charged with the Bloody Sunday assassination of British military prosecutor Captain G.T.

[12] Following its two for one policy that required the killing of two members of the Royal Irish Constabulary (RIC) for every Republican executed, the West Connemara flying column of the IRA fatally shot RIC Constables Charles Reynolds and Thomas Sweeney at Eddie King's Corner on 16 March 1921.

In response to the RIC's request for assistance through the Marconi wireless station, a trainload of Black and Tans arrived via the Galway to Clifden railway in the early hours of St Patrick's Day, 17 March 1921, and proceeded to "burn, plunder and murder".

In addition, all petrol was confiscated, roads barricaded and made impassable, railway bridges were blown up and telegraph lines cut.

On 13 October, Republicans burned down the Recess Hotel and nearby Glendalough House to prevent the National troops from using them as billets.

The townspeople again welcomed the National Army and soon repairs started on bridges and the Galway to Clifden railway line.

Regular coach services are provided by Bus Éireann and Citylink, connecting Clifden with Galway city.

[22] In 1989, a group of Clifden businessmen issued shares for a company and applied for planning permission for a 1,200-metre runway and associated buildings at Ardagh.

Galway County Council refused planning permission for the airport due to feared damage to the natural beauty of the area, and because it was designated an 'Area of International Scientific Importance' (ASI).

The 'Clifden Airport Co.' appealed and as a consequence of the legal proceedings, which went all the way to the Supreme Court, ASI designations were found to be unconstitutional.

[27] Community Arts Week in late September offers poetry reading, lectures, recitals and traditional music.