Charles Hose arrived in Sarawak in 1884, a twenty-year-old cadet in the civil service of Charles Brooke, the second White Rajah. The Brooke dynasty was one of the stranger experiments in colonial history: a family of English adventurers who governed Sarawak as their personal kingdom from 1841 to 1946, holding it not as a crown colony but as a private domain recognized by the British government. Young Hose was posted to the newly created Baram District, a territory recently ceded to Brooke by the Sultan of Brunei. The region was remote, riverine, and volatile, home to Kayan, Kenyah, Kelabit, and Penan communities whose relationships with each other and with the Brooke administration oscillated between cooperation and armed resistance. Hose proved himself capable enough to be promoted to Resident of the Baram in 1891, making him the senior government official in a district larger than some European countries.

Hose had the fort constructed in 1898 from belian, an ironwood so dense it sinks in water and resists termites for centuries. The site was chosen for its commanding view of the Baram River, the district's only highway, from which the Resident could monitor the traffic of longboats, trade goods, and potential trouble. Two cannons guarded the frontage, aimed downriver. The fort served triple duty: as administrative headquarters for the district, as the Resident's personal quarters, and as a signal to the surrounding communities that the Brooke government intended to stay. It was also, in 1899, the site of a formal peace accord between rival ethnic groups, orchestrated by Hose. The idea was characteristically pragmatic: if the tribes could be brought together under a shared agreement, the government could redirect the energies spent on feuds toward more productive purposes.

Hose was no ordinary colonial administrator. During his 24 years in Sarawak, he pursued a parallel career as a zoologist and ethnologist, collecting specimens, taking photographs, and compiling observations that would fill several books. His most significant publication, The Pagan Tribes of Borneo, gave Western readers their first detailed account of the region's indigenous cultures, including frank discussions of headhunting, tattooing, and social organization. His zoological collections, many donated to the British Museum, included birds, mammals, and insects from the Baram's remote interior. Hose documented the communities he governed with a camera as well as a pen, and his photographs of Kelabit salt-making, longhouse life, and tribal portraiture from the early 1900s survive in the museum that now occupies his fort. He left Sarawak in 1907 and died in England in 1929, but his name remains attached to the hilltop he chose more than a century ago.

The original fort survived nearly a century before fire destroyed it in 1994. Reconstruction began immediately on the same hilltop, and the replica was completed and opened as the Baram District Museum in 1997. The building has been gazetted as a cultural heritage site under Sarawak's Cultural Heritage Ordinance of 1993, a designation that protects both the structure and its contents. Inside, exhibits trace the cultural heritage of the Baram's communities: Kayan beadwork, Kenyah wood carvings, Kelabit megalithic traditions, and the material culture of the Penan, Borneo's last nomadic forest people. The Baram Regatta that Hose invented still runs, now a biennial event that draws longboat teams from across the region. War canoes still race on the brown water below the fort, though the paddlers come for trophies rather than territory. The mock battles have become cultural performances, and the feuds they were designed to replace are the subject of museum placards rather than living memory.