The calculated distance (air line) between Kisumu and Ongata Rongai is approximately 165 miles respectively 265 kilometers.
By car or train, the actual journey to Ongata Rongai is certainly longer, as only the direct route (as the crow flies) between Kisumu and Ongata Rongai has been calculated here.
Air line (approximately)
265 kilometers
143 nautical miles