During the late Oligocene, around 25 million years ago, our primate ancestors, the Hominoidea (apes and humans) and Cercopithecoidea (Old World monkeys), branched off from a common ancestor in East Africa. By the early Miocene (approximately 23-16 million years ago), both groups had diversified significantly, making this time period crucial for understanding our deep evolutionary history and the connection between our early primate ancestors and their environment. In a remote area of west Turkana, known as Loperot, lies a unique opportunity to delve into the early Miocene primate environment. The site yields a variety of ancient fossils, including important catarrhine specimens, the oldest record in Africa of a shovel-tusked proboscidean (Platybelodon sp.), and a ziphiid whale that was able to swim from the open ocean to Loperot, which now sits more than 750km from the nearest coast. Radioisotopic dating reveals that the Loperot fossils are older than 17 million years.  Our research combines geochemical data from ancient soils, stable isotope analysis, and detailed sedimentology to reconstruct the early Miocene environment of Loperot. We discovered a dynamic landscape shaped by a perennial river system (home to Nile oysters and large crocodiles) that supported patches of riparian forests within a broader open ecosystem under semi-arid conditions. This environmental setup contrasts sharply with other known early Miocene primate sites in that the C3 forests that surrounded the perennial rivers were restricted in size, and therefore could not support a wide variety of forest-dwelling species. This comprehensive environmental reconstruction of Loperot provides new evidence that the African climate during the early Miocene varied greatly by region, and that our primate ancestors exploited diverse habitats.