Named after the turn of the 20th century British hunter, Frederick Selous, this rarely visited park nick-named "the Secret Eden" is far off the beaten path, and well worth the time to get there. Established in 1922 as a preserve for big game trophy hunters, the trackless wilderness still remains largely unexplored. It is the world's largest game reserve and walking safaris are encouraged. Low lying flood plains and wide sand rivers lined with doum palms gives a prehistoric feel to this 5000 square km park. The crocodile infested Rufiji River and its tributaries form a network of large lakes that are ideal for boat safaris. Because of the low human population density populations of elephant (reportedly up to 100, 000 elephant here), buffalo, roan and sable antelope, hippo, and packs of wild dog and the occasional rhinoceros are often seen. The bird watching is spectacular with 350 catalogued species.

The best time to visit is from June to February. It's a 7-hour drive from Dar es Salaam, or a 35-minute charter flight. A must see is Stiegler's Gorge, where the Rufiji and the Great Ruaha river meet. Adventurers with steely nerves can cross a cable that spans the gorge. For the angler's, a fishing trip on Lake Tagalala is a must.
All camps and lodges are concentrated near Stiegler's Gorge, where boat trips are available. Lodges and camps are closed due to rains from April to June.