Garissa is the capital of Garissa County, Kenya. It is situated in the former North Eastern Province. The Tana River, which rises in Mount Keny…Garissa is the capital of Garissa County, Kenya. It is situated in the former North Eastern Province. The Tana River, which rises in Mount Kenya east of Nyeri, flows through Garissa. The Bour-Algi Giraffe Sanctuary, situated 5 km south of Garissa, is home to endangered wildlife including the Rothschild giraffe, gerenuk and other herbivores including Kirk's dik-dik, lesser kudu, warthog and waterbuck.