Michael McCarthy started trading on the square in 1860. He had begun as a general merchant - flour, sugar, hardware, candles - and his business grew as it picked up custom from the Royal Navy base across the harbour at Berehaven. The grocery added a license and became one of the first proper public houses in Castletownbere. His youngest son, Denis Florence McCarthy - known to everyone as D. F. - took it over and made it the bar his grandchildren still pour from. When the craftsmen building the Church of the Sacred Heart up the street had spare hours between 1907 and 1911, D. F. brought them in to fit out the interior - the timber bar, the shelving, the joinery that still defines the room. To distinguish themselves from a neighbour with the same surname, the family changed their spelling from Mc to Mac. It stuck.

D. F.'s son Aidan MacCarthy left Castletownbere to train as a doctor and joined the RAF medical service before the Second World War. What followed reads like several lives crowded into one: he was at Dunkirk and evacuated with the British Expeditionary Force; survived a torpedoed ship; ended up a prisoner of the Japanese after the fall of Java; was being transported to a labour camp on a freighter that was itself torpedoed; and was interned at a camp at Fukuoka, on the Japanese island of Kyushu. He was there on 9 August 1945 when the bomb fell on nearby Nagasaki. He survived that too. At the formal Japanese surrender of the camp, a Japanese officer offered him his ceremonial sword as a personal act of surrender - a gesture that, in the codes of the time, asked the recipient to spare the giver's life. MacCarthy took the sword and the officer lived. The sword came home to Castletownbere. It hangs behind the bar today.

Pete McCarthy was not related. He was a London comedian and broadcaster of Irish descent who set off across the country in the 1990s following his own self-invented rule about bars with one's surname above the door. Chapter six of McCarthy's Bar (published 2000) describes the evening he spent in the Castletownbere pub - the music that went on past closing, the conversations that bent and folded into each other, the sense of a place that did not need to perform itself for visitors because it was already busy being what it was. The book was published in 1998 and became the kind of success that brings tour buses. The bar made its peace with the fame. It still does not advertise.

By the late 1970s the family had begun to thin out. Aidan died eventually in 1992 - he had also written his own war memoir, A Doctor's War. In 1979 his daughter Adrienne MacCarthy moved back to Cork to take the bar over after the death of an uncle and to keep it from closing. Her sister still lives in the town. The two daughters between them run the shop and the pub and what amounts to a small museum of the family's century and a half on the square. The fridge full of dairy products is, as Pete McCarthy noted, also a fridge for prosecco. The shelves above it carry the same brands they have for decades. Twelve staff work the room. Food is served between 11 a.m. and 4 p.m. There is live music most nights.

During the COVID-19 pandemic in 2020, MacCarthy's stayed closed for the longest stretch in its history - longer than the wartime years, longer than any pause in 160 seasons. When the pub finally reopened, the front room was reconfigured for one-way passage, with sanitisers and screens, the way every other Irish pub had to be reconfigured. The grocery side never quite stopped, because people still needed bread. The bar came back. The sword stayed where it was. Travellers still pass the door, read the name above it, and stop in because of a book they read twenty-five years ago. Locals come in because they always have. The two streams have shared the floor for a long time now, and the floorboards are used to both.