Against the backdrop of major political transformations between Sudan and South Sudan, localized conflicts in South Sudan’s Greater Upper Nile region have been largely overlooked by the international community. This briefing paper focuses on fighting during 2011 in Mayom County between the Sudan People’s Liberation Army and armed opposition forces originally loyal to Peter Gadet and other Nuer commanders. The briefing documents serious human rights abuses, as well as the origins and where possible supply routes of key weapons and munitions used by the different parties to commit such violations.