Ridgwell Cullum (pseudonym of Sidney Groves Burghard; 13 August 1867 – 3 November 1943) was a British writer who wrote a large number of adventure novels over more than 30 years, usually set in sparsely populated regions of the United States or Canada.

Sidney Groves Burghard was born in London on 13 August 1867.

[1] He left home aged 17 to join a gold rush in the Transvaal in South Africa, where he became involved in the conflict between British and Boer settlers.

Later he travelled to the scene of another gold rush in Yukon in north-west Canada and spent a number of years cattle-ranching in Montana, United States.

His first novel The Devil's Keg, set in Alberta, Canada, was published in 1903.