The only river that runs all year
The Mara River cuts across the northern Serengeti on its way from Kenya to Lake Victoria. It is famous for one thing, and important for a different one.
UNESCO’s assessment of Serengeti National Park states it plainly: only one river, the Mara, flows perennially through the park. In a landscape of 14,763 square kilometres with 900 to 1,000 millimetres of rain a year concentrated into distinct seasons, that is a remarkable dependency, and UNESCO names it among the major management concerns for the property — a single perennial river which is transnational and which currently faces multiple human-mediated cross-boundary threats. An extension of the park boundary to reach Lake Victoria, giving animals a corridor to water in drought years, is recorded as planned for the future.
That is the part of the Mara story that does not appear on itineraries, and it is the more consequential half.
The crossings
The other half is what everyone comes for. The herds cross the Mara in both directions during the northern phase of the Great Migration, generally in the second half of the year, and the crossings are the single most photographed wildlife event on the continent.
Several things about them are worth knowing before a trip is built around one. The herds do not cross on a schedule; they gather at the bank and may wait for days. They cross back and forth rather than once. The river is held by very large Nile crocodiles, which is a large part of why the crossings look the way they do. And a crossing that is happening is likely to be watched from a line of vehicles, because driving off the road is prohibited in the Serengeti and everyone is therefore confined to the same tracks.
The great migration safari guide covers how to plan around all of that. Three nights in the north during the crossing window is a working minimum; one night is close to a lottery ticket.
Reaching the river
The Mara sits at the far end of the park from Arusha. TANAPA’s airstrips at Kogatende and Lamai serve the northern Serengeti directly, and for most itineraries a light aircraft leg is the difference between three usable days on the river and two spent driving to it — see scenic flights. By road the northern gates are Lamai, Machochwe and Klein’s.
Outside the crossing months the Mara country is one of the quietest parts of the park, which is its own argument. The river still holds hippo and crocodile, the hill country around it is greener and more wooded than the plains, and there are far fewer vehicles.
Common questions
When do the herds cross the Mara?
Generally during the northern phase of the migration in the second half of the year, but the timing shifts between years and crossings happen in both directions. No date can be published.
Is the Mara the Serengeti’s only river?
It is the only one that flows all year. UNESCO records this as a major management concern for the park, because that single perennial river is transnational and under cross-boundary pressure.
Can you watch a crossing from close up?
From the road network only. Off-road driving is prohibited in the Serengeti, so vehicles concentrate at the accessible crossing points and a good sighting is usually a shared one.