He held office from October 1890 until September 1892, the period of the founding of Fort Salisbury (now Harare) after the arrival of the Pioneer Column.

[2] In the 1880s he took part in several exploratory expeditions to Burma, Indo-China and southern China, for which he was awarded the 1884 Founder's Medal of the Royal Geographical Society.

From 1900 to 1901, he and his new wife Ethel travelled in the Pacific —the Dutch East Indies, Borneo, Philippines, Japan – returning to England via Siberia.

In 1913, Colquhoun inspected the Panama Canal construction work and carried out one last mission for the Royal Colonial Institute in South America before his death in London on 18 December 1914.

[5] After his death, his widow remarried John Tawse Jollie and settled in Southern Rhodesia, where she became the first female parliamentarian in the British overseas empire.