Meru is a savanna National Park, 35km east of Maua town in the north eastern lowlands below the Nyambeni hills. Meru is part of a complex of protected areas along the Tana river that includes the adjacent Bisanadi and Mwingi National Reserves (to the east and south respectively), Kora National Park and Rahole National Reserve. The wetter North Western sector is hilly, with rich volcanic soils.

The land flattens towards the East, where grey alluvial volcanic soils appear. The area is crossed by numerous permanent streams, draining from the Nyambenes and flowing in parallel between tounges of lava, south eastwards towards the Tana River. As well as the many streams that cross it, the park is bounded by three large rivers: the Tana to the South, the Ura to the South West and the Rojeweru to the East. There are several prominent inselbergs of basement rock, notably Mughwango and Leopard rock.

A section of the park has been designated as a wilderness area in which are no roads.

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