The land of the old Zone 3 sits in a vast flat basin - grassland and swamp, cut through by the Pibor and Baro rivers as they flow west toward the Sudd. Each year the rains come. Each year the rivers overflow, and the plains become inland seas tens of kilometres across. The Nuer people of Akobo and Jikaw woredas have always responded the same way: they move. Men, women, children, and every head of cattle migrate to patches of higher ground until the floodwaters recede, living on what the herds can provide. Agriculture here is almost impossible; livestock is the backbone of the economy. There are no agricultural cooperatives, no documented roads, and little other infrastructure. The rivers give and the rivers take back.

The 1994 Ethiopian census recorded 68,224 people living in Zone 3, ninety-eight point three eight percent of them Nuer and one point five six percent Anuak. The Nuer language was the first language of nearly everyone interviewed. A decade later, the 2005 estimate put the population at 88,784 - still overwhelmingly Nuer, with an area of roughly 6,000 square kilometres and a population density of less than fifteen people per square kilometre. Only two percent of inhabitants lived in anything identifiable as a town. The rest lived the way Nuer pastoralists had lived for centuries - in cattle camps, in homesteads on the edge of the flood line, in settlements that shifted with the water.

The religious statistics from the 1994 census are worth pausing on. Nearly sixty-five percent of the population identified as Protestant - the Nuer having embraced various strains of evangelical Christianity brought by missionaries during the twentieth century. Just over fifteen percent still practised traditional religions: the old Nuer understandings of Kwoth, the divine, expressed through cattle sacrifice and the interpretations of the leopard-skin chief. Less than four percent were Ethiopian Orthodox, and just over one percent Catholic. That mix - new faith alongside old, neither fully displacing the other - describes a great deal of contemporary Nuer life.

At some point before 2001, Ethiopian administrative reorganisation abolished Zone 3 entirely. The Nuer-majority woredas of Akobo and Jikaw, together with most of the former zone, were consolidated into the new Nuer Zone. Some eastern sections went to the Anuak Zone. The towns mentioned in old records - Tergol, Telut - retained their names on maps but found themselves in different jurisdictions. The rivers remained where they had always been. The line between Ethiopia and South Sudan, now an international border where once it was merely the edge of a disputed frontier, cut across ancient Nuer grazing and fishing ranges with administrative indifference.

The Gambela Region as a whole occupies the lowland frontier where the Ethiopian highlands give way to the swamps of the White Nile. It is the hottest, wettest, and lowest corner of Ethiopia, ethnically and ecologically distinct from the highlands that govern it. From a cruising altitude over the Sobat basin, the former Zone 3 appears as flooded plain in one season and as patchwork grassland in another. The rivers that defined its borders - the Pibor coming up from the south, the Baro flowing west - meet not far north of here to form the Sobat, which carries Ethiopian rainwater across South Sudan to join the White Nile in the Sudd. The zone's name has been retired. The flood still comes.