Margaret Anne was the daughter of Thomas Brown. In 1873, She married George Frederick Armstrong in Headingly St. Michael, Yorkshire. At the time, George was the first professor of civil engineering at McGill University’s Applied Science School. The couple lived in Montreal for five years, and their first child, George Cyril, was born there. In 1876, the family moved back to England, where George had been named chair of the engineering department at Yorkshire College. In 1880, Margaret gave birth to a second child, Margaret Muriel. The next move came in 1885 when her husband was appointed Regius professor of engineering at the University of Edinburgh. Son George and Muriel were already grown up when Margaret Anne became a widow in 1900.