On 16 October 1890 Michael Collins was born near Sam's Cross, a tiny hamlet in West Cork, named after Sam Wallace, a local highwayman. Sam's Cross lies between Rosscarbery and Clonakilty. Here, in a picturesque valley between river and sea, the young Michael grew up. As a lad, he spear-fished for salmon in the river and played among the cliffs above Black beach and at Cliodhna's Rock. But, as was typical of the times, Michael never learned to swim. Michael's father, Michael John Collins was sixty years old when he married a local girl, Marianne O'Brien. Marianne was only twenty-three, but they were apparently happy and went on to have eight children. Michael, the youngest, was born when his father was seventy-five. Michael's father was a farmer by trade, not rich, but living comfortably for the times on a holding of ninety acres. The farm was called Woodfield after a hill in the area. When Michael was six, his father died.

Michael attended national school at Lisavaird, and the schoolmaster there was to have a large influence on Michael's life. For this schoolmaster, Denis Lyons, was an active member of the Irish Republican Brotherhood, a secret organisation dedicated to ousting the British from Ireland, by force if necessary. Lyons and the local blacksmith, James Santry, another Fenian, were Michael's first tutors in giving him a sense of pride of the Irish as a race. Throughout Michael Collins' brief life, Irishness was the thing that held the greatest meaning for him.
Big for his age, Michael had a keen mind as well as a fit, athletic body.

He loved to read. His sister, Mary Ann, heightened his interest in the struggle for nationalism, and because of her, he devoured the writings of men such as poet and Nationalist, Thomas Davis. Worried that he might fall in with a bad sort, his mother sent him to Clonakilty to study for the Post Office examinations and to live with his sister Margaret. Here he worked briefly for his brother-in-law who owned the West Cork People, a newspaper of the area. Michael learned typesetting and wrote articles of local sporting events. After a year and a half, he went to London where he lived with his sister Hannie, in West Kensington and worked for the Postal Savings Bank in West Kensington. He was fifteen. Michael would spend the next nine years in London.