The Simpson Family fonds consists predominantly of documents, photographs, and artifacts pertaining to the operations of a succession of sawmills and wood manufacturing plants founded by Stanley Merriam Simpson (b. 10 August 1886, d. 20 March 1959) and assumed by his son, Horace B. Simpson (b. 17 March 1917, d. 8 September 1994) in the Okanagan area. In later years, these enterprises were controlled by corporations such as Crown Zellerbach, Fletcher Challenge, and Riverside Forest Products. Today, on the original SMS Ltd. site at Manhattan Point on the shore of Okanagan Lake in Kelowna, BC, Tolko Industries still operates.

S.M. Simpson founded what would later become S.M.S. Ltd. in 1913. The company was incorporated as S.M. Simpson Ltd. on 24 January, 1924 under certificate no. 7233 of the British Columbia Companies Act. S.M. Simpson, having gotten a start making sag free screen doors, later diversified the company's interests to concentrate on manufacturing wooden boxes to accommodate the fruit based economy of the Okanagan Valley. Throughout the 1920s to 40s, S.M.S. Ltd. purchased various sawmills, including Trautman Garraway in Peachland, Kelowna Sawmill Company, Peachland Sawmill & Box, McLean Sawmills, Eagle Pass Lumber, R&L Lumber, and Lumby Timber. At its height, operations included logging and forestry initiatives including FML #9 near Bear Creek, a veneer factory, a box factory, a plywood plant, a Kelowna Sawmills retail outlet.

The digitized portion of the fonds is comprised of a photographic record that documents the wood processing entity established by S.M. Simpson.