Mayom County occupies the northwest of Unity State, in the Greater Upper Nile region. Its headquarters is Mayom town; other significant settlements include Tam, Mankien, and Wang-kay, with villages like Rier, Thargana, Buoth, Wicok, and Toic scattered through the grassland. The county's terrain is flat savannah, seasonally flooded in the rainy months, cut by cattle tracks worn into the soil over generations. What makes it strategically valuable is invisible from the air: Mayom sits inside the Block 4 oil concession, south of the Kaikang oilfield. For the Bul Nuer communities who make up most of the population, that geology has been less a blessing than a target, turning their grazing lands into a theater of negotiation between armed forces that rarely consulted them.

Trouble arrived before the Second Sudanese Civil War did. Around 1982, encouraged by the Khartoum government, Baggara herders from the north began arriving in the Mayom region armed with automatic rifles. That year they stole about 500 cattle from the local Nuer and Dinka communities, an early outbreak of raids that would worsen for decades. In March 1985, combined SPLA and Anyanya II forces under Major Bul Nyawan defeated a Baggara raiding party, which led to a period of relative peace. The real damage came in 1987 and 1988, when the combined pressure of the army, Anyanya II, and the SPLA campaigns resulted in famine. Villages were burned. People were killed in large numbers. Whole communities were displaced. No relief agencies were present to record the scale of the hunger, and so the famine of 1987-88 lives mostly in the memories of its survivors rather than in international archives.

In preparation for the January 2011 independence referendum, the county ran a disarmament drive. 1,700 guns were handed in, most of them AK-47s that had accumulated during the civil war. County Commissioner Colonel John Madeng Gatduel said the disarmament cleared the way for peaceful negotiations between payams (administrative units) that had previously been in conflict. The referendum result in Mayom was decisive: 98 people voted for continued unity with Sudan, while 80,364 voted for secession. The margin, almost 825 to 1, was even more overwhelming than South Sudan's already lopsided national result. Whatever the Mayom Declaration would soon claim about corrupt gangs in Juba, the people of Mayom had voted, clearly and in numbers, for the country that declaration denounced.

In March 2011 Commissioner Gatduel was replaced by Charles Machieng Kuol, the son-in-law of the state governor. The Bul Nuer community, not consulted about the appointment, publicly objected. In April, a Misseriya raiding party from the north attacked an SPLA base claiming they were retaking 1,700 cows the army had stolen. Eleven Misseriya men died and 22 were injured. Twenty SPLA soldiers died in separate clashes with Gadet's rebels who had taken and then burned a Mayom village. The state government ordered all Sudanese nationals working in the oilfields to leave Unity State immediately. By late May, when Machieng reported that 7,800 homes had been burned in the Loath, Wanam, and Bora bomas and blamed the SPLA, the government response was to dispute the accusation, accept the cross-fire explanation offered by SPLA Major General Koang Chuol, and (by July) to sack Machieng. For the families whose homes had been destroyed in the cross-fire, the question of which side had lit which fire mattered less than the fact that they were still homeless when the rains came. Mayom County's history, like so much of Unity State, has been written in rebuildings.