Patrick (Pat) Fletcher junior should not be confused with his father, Patrick senior* (both were surveyors), or with his elder brother Robert Alexander*, who had a very similar early career. Patrick junior, like his brother, received his education at St Andrew's College, Grahamstown, and passed the matriculation examination of the University of the Cape of Good Hope in 1885. The next year he passed the university's examination for the Certificate of Proficiency in the Theory of Land Surveying. Again like his brother, he completed an apprenticeship with the Cape railway engineer Richard E. Brounger and became an associate member of the (British) Institution of Civil Engineers. He married Ida Eliza McDonald of Queenstown, with whom he had three sons and two daughters, while his brother married her sister Annie. Both brothers were admitted as land surveyors in the Cape Colony in 1888.
Patrick was engaged on railway construction in the Cape Colony, Orange Free State and Transvaal to 1893, as was his brother. He then entered Matabeleland with the Pioneer Column and in January 1894 laid out the town of Bulawayo. He also served in the Anglo-Matabele War in 1893, the so-called Matabele Rebellion in 1896, and the Anglo-Boer War in 1900. In 1894 he and William M. Espin* founded the firm Fletcher & Espin, which his brother Robert joined soon afterwards. The firm carried out extensive trigonometrical surveys between 1894 and 1907 in Matabeleland and Mashonaland (in present Zimbabwe) and in the northern Transvaal. Both brothers were justices of the peace for Matabeleland. Patrick was admitted as a land surveyor in the Transvaal in October 1903. He was an early member of the Institute of Land Surveyors of the Transvaal, which listed him as residing at Mara, Transvaal, in 1905. The next year his address was Grenfell Camp, via Louis Trichardt, but by 1909 he was back in Bulawayo.
Various letters, diaries and notebooks relating to Patrick Fletcher, dated between 1886 and 1915, are housed in the National Archives of Zimbabwe, with photocopies in the libraries of the University of Cape Town.