On the border with Uganda is Nimule National Park. The Nile River cuts along the eastern border of the park for 48 kilometers. The road from Uganda to Juba cuts along the eastern border of the park next to the Nile. The park has 41,000 hectares or 101,270 acres and was originally created to protect the White Rhino, which is now extinct. The park is the most accessable of South Sudan’s parks. A three hour drive from Juba (190 kilometers/118 miles)), on a newly reconstructed paved road (the only paved road in South Sudan), makes visiting the park, all year, possible.
A herd of elephant have made the park their home, realizing they are safe in the park. Most often they are found on an island in the Nile called Opekoloe. This herd of about 70 animals wanders back and forth across the border with Uganda.
Ocassionally the Uganda Wildlife rangers must chase the elephants back into South Sudan, when the elephants raid the farms of Ugandan villages. See this link about the south sudan elephant herd being returned from Uganda