The Karisoke Research Center was established by Dian Fossey in 1967 and is the site of the world's longest continuous primate study. Access to the site itself — at 3,000m in the bamboo and hagenia forest between Karisimbi and Bisoke — requires a special hike permit that includes a visit to Fossey's grave and the gorilla cemetery where the early study animals are buried, including Digit.
The hike to the site is demanding (three to four hours each way) and must be done with a certified guide. The forest at this altitude is dense and often misty; the ground is soft volcanic soil. At the site, the original camp has long since been dismantled, but the gorilla cemetery is maintained. Fossey's grave is marked with a simple stone next to her beloved gorillas. The atmosphere is affecting.
The Karisoke Research Center is now operated by the Dian Fossey Gorilla Fund, which continues long-term research on the Volcanoes National Park gorilla families. The fund also supports anti-poaching work and community development in the villages surrounding the park. You can visit the fund's Ellen DeGeneres Campus in Musanze, which has an excellent interpretive exhibition on the gorillas and Fossey's work, without trekking to the mountain site.