What it is
The basin of the Omo River in the far south-west, running down towards Lake Turkana. The useful bases are Jinka, Turmi and Omorate, and the markets at Key Afar, Dimeka and Turmi are what you plan the week around.
Why go
The Hamar, Karo, Mursi, Dassanech, Ari and others have distinct languages, dress and ceremonies, Hamar bull-jumping among them. Meeting people whose lives are organised around cattle and a river rather than around a town is the whole draw.
When to go
October to March; in the rains some crossings become impassable. Be honest with yourself about the ethics before you book. Photography here is transactional — a fixed fee per photograph is standard, and the encounter can feel like a transaction from both sides. Some villages see several vehicles a day. If that will sit badly with you, go elsewhere. If you go, use an operator with a long-standing relationship with the same communities, agree the terms before you lift a camera, spend more time in fewer places, and go to the markets, where people are there for their own reasons rather than yours. The driving is long and rough: Addis to Jinka is two days by road, or a short flight.
Most people stay 4-6 nights.