evidence: What about the Kafia Kingi enclave? I defer to Edward Thomas, who wrote an entire book (PDF, 2010) on this remote and sparsely inhabited region of Africa, long used as slave hunting grounds by Arab slave traders. Kafia Kingi was part of southern Sudan at independence in 1956, but in 1960 jurisdiction over the area was transferred to northern Sudan. [...] Because the Wikipedia/OSM border dataset is based on Sudan’s provincial boundaries as they existed in 2011, not in 1956, they do not show Kafia Kingi as part of South Sudan — it stays with Sudan’s province of South Darfur. This is an error. You could even argue that South Sudan’s claim to Kafia Kingi is stronger that that for Abyei, because Kafia Kingi belonged to southern Sudan in 1956 and thus its transfer requires no further discussion. This view is apparently held by the CIA; its World Fact Book entry depicts Abyei as disputed but Kafia Kingi as integral to South Sudan: