The annual convergence of some wild animals at the Oli River in Kainji Lake National Park was studied. Animal population were determined using the King census method. Indirect method of counting involved the use of footprint and faecal count. Sample drives were carried out as from 7.00 h in the morning to 18 h in the evening. Data were collected both in the dry and wet seasons. There were significant differences (p<0.05) in animal population and distribution between the dry and wet seasons. Antelope were the most common animals while elephant were the least. Different species of birds were also sighted at different hours of the day. There was a positive correlation (r = 0.022) between animal visit to Oli river and the season of the year. Hippopotamus and different species of reptiles were found within the riverbanks while dicker was the least frequent throughout the year. The flooding of the river was also found to affect animal population. Oli River, the biggest river that runs across the park, is of great ecological benefit to the park. It was concluded that Oli River provides water for various species of wildlife both during the dry and at wet seasons. It also supports vegetation, which provides protective cover and food for wildlife. This greatly explains why there is a high convergence of animals at its bank all the year round.