Thomas and Elizabeth Greenhow lived in Newcastle's fashionable Old Eldon Square. The couple had several children; Frances and at least two boys. Henry Martineau Greenhow (1829–1912) followed his father into medicine. He joined the Indian Medical Service and spent his career in British India, rising to surgeon major. His garrison withstood the Siege of Lucknow, a key part of the Indian Rebellion of 1857. Another brother, William Thomas Greenhow (1831–1921) became a judge. The siblings' first cousin Edward Headlam Greenhow was a physician-academic, who made his mark in epidemiology and public health.