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.

Between 2005 and 2007, Garissa cattle farmers earned over KES1.8 billion in sales in domestic and overseas markets.

[12] The city is represented by Aden Bare Duale, a Somali Member of Parliament for the Garissa Township Constituency in the National Assembly of Kenya.

During the colonial era, Garissa, as well as other parts of NFD, were collectively conferred to as the British East Africa province of Trans-juba, and would subsequently be referred to as Jubaland, which split into two in the mid 1920s.

The city lies along the Tana River, and has a hot climate due to the low elevation and distance from cooler coastal areas.