Harold StJ.L. Winterbotham, son of Reverend Canon R. Winterbotham, was educated at Fettes College, Edinburgh. In 1896 he entered the Royal Military Academy at Woolwich (near London) and obtained his commission as a second lieutenant in the Royal Engineers in December 1897. He was subsequently promoted to lieutenant (December 1900) and captain (December 1906). During the Anglo-Boer War (1899-1902) he saw active service in South Africa and was awarded the Queen's Medal with three clasps, but was soon invalided to England as a result of enteric fever. From 1902 to 1906 he was stationed on St Helena. As co-author with Major C.F. Close* he took part in writing a Text book of topographical and geographical surveying (1905), which became a standard work (3rd ed., 1925). He was married to Daisy Stocking, with whom he had two sons and two daughters.
In August 1908 Captain Winterbotham succeeded Captain L.C. Jackson* as officer in charge of the Colonial Survey Section, which conducted a topographical survey of the Orange River Colony (now the Free State). He and his men completed the secondary triangulation and plane table survey of the colony. The work led to the compilation of the Topographical series of the Orange River Colony, on a scale of 1:125 000, of which 43 sheets were published between about 1907 and 1929. These were the best maps of the territory for decades. Winterbotham later published papers on "Topographical survey in South Africa" (South African Survey Journal, 1926) and, with G.T. McCaw, "The triangulation of Africa" (Geographical Journal, 1928).
After leaving South Africa in 1911 Winterbotham was attached to the Ordnance Survey in Southampton until the outbreak of World War I in 1914. During this period he published "An investigation into the accuracy of the principal triangulation of the United Kingdom" (Ordnance Survey Professional Papers, 1913, 20p). For the duration of the war, until 1918, he served in the Royal Engineers and was promoted to major (October 1914). He was employed on a variety of survey and related duties, but his most interesting work, as the officer in command of the Ranging Section of the Royal Engineers, was concerned with the development of sound ranging. From 1922 to 1929 he was head of the Geographical Section of the General Staff. During 1929-1930 he inspected the Colonial Survey Departments and from 1930 to his retirement in 1935 was director-general of the Ordnance Survey, with the rank of brigadier. He had much to do with the adoption of a single orthomorphic projection for all the Ordnance maps of Great Britain and was also concerned with the design of the "Tavistock" theodolite. Just after his retirement he published A key to maps (London, 1936, 208p). From 1930 to 1945 he was the general secretary of the International Geodetic and Geophysical Union. During World War II (1939-1940) he compiled reports on Albania and the Belgian Congo for the Naval Intelligence Division. He was honoured as a companion of the Distinguished Service Order (DSO, January 1916), a companion of the Order of St Michael and St George (CMG, 1918) and a companion of the Order of the Bath (CB, 1935). In 1929 he was awarded the Victorial Medal of the Royal Geographical Society and in 1939 George Washington University conferred an honorary Doctor of Science (DSc) degree upon him.