Kate was born at Loughaun, a crossroads near the village of Dunkerrin and the town of Moneygall, in County Offaly, Ireland. Dunkerrin Catholic Church records show that her parents, Michael and Margaret Shelley, married on February 24, 1863, and she was baptized on December 12, 1863. Her grave marker says she was born on September 25, 1865 and died January 21, 1912. The family name was originally spelled Shelly, which is how she wrote her name, but the spelling Shelley was later adopted.