This atlas contains a summary of findings from the twelfth round of Mobility Tracking conducted across South Sudan through key-informants based assessment at payam and location level between as of December 2021. Mobility Tracking quantifies the presence of internally displaced persons (IDPs) and returnees in South Sudan in displacement sites and host communities. IOM DTM mapped a total of 2,229,657 IDPs (including 7% previously displaced abroad) and 1,924,368 returnees (including 33% from abroad) in 3,654 locations across South Sudan as of December 2021.