Kulubnarti - "Kulb island" in Nubian - is about one mile long, sitting in the Nile about 120 km southwest of Wadi Halfa and just north of the Dal Cataract. It is part of the village of Kulb, with Kulb West on one bank and East Kulb on the other. Before the Aswan High Dam was built, Kulubnarti was only an island during the Nile's annual flood. Today it remains technically an island only when the level of Lake Nubia - the Sudanese name for the Aswan reservoir - reaches its peak. The usual Nubian band of fertile alluvial farmland is missing here; the island sits in the Batn-El-Hajar region, rugged and stony. Agriculture is limited to small pockets. People live at the north and south ends of the island. The altitude is about 200 meters above sea level, and there are still castles, kourfas (fortified dwellings), houses, and churches from earlier centuries.

Nubia converted to Christianity by the late sixth century, and Christianity was the dominant faith for nearly a thousand years. In the fourteenth century, when Islam took control of territory south of the Third Cataract, Christianity persisted north of that line - including at Kulubnarti - into the fifteenth century. Kulubnarti has been continuously inhabited since about 1100 AD, making it the only Nubian location with archaeologically demonstrable continuous occupation from the Middle Ages to modern times. Two notable buildings survive from the Christian era: the Kulubnarti fort, a fortified house that was converted into a castle, and the 13th-14th century domed Kulubnarti church. Graffito incised into the church walls appears in three languages - Greek, Coptic, and Old Nubian - evidence of the trilingual literacy that defined late Christian Nubia. For people who wanted to remain Christian when the surrounding region was becoming Muslim, a small island on a hard stretch of river was a reasonable refuge.

In 1979, a joint expedition between the University of Colorado and the University of Kentucky, led by Dennis Van Gerven, excavated over 400 burials from two cemeteries at Kulubnarti - site 21-S-46 on the island and site 21-R-2 on the adjacent mainland. At first, the island cemetery was thought to be Early Christian and the mainland one Late Christian. Later reanalysis of textiles and radiocarbon dates showed both actually date from the Early Christian period, though parts of the mainland cemetery are still used by modern villagers. The human remains from Kulubnarti have since become one of the best-studied bioarchaeological collections in the world. They have contributed to global understanding of morphological variation, biological stress, and the health and disease profiles of pre-industrial populations. Paul Sandberg's isotopic analysis of the two cemeteries looked at health differences between them. Other studies examined trauma, nutrition, and genetic drift.

In 2015, Kendra Sirak and colleagues published the first ancient DNA analysis of a Christian-period Kulubnarti individual. The sample was most closely related to Middle Eastern populations - a surprising result for a Nubian context. A 2021 study expanded the genetic sample to 69 individuals. The population turned out to be a blend of roughly 42.5% Dinka-related (Nilotic) ancestry and 57.5% West Eurasian-related ancestry. The mtDNA and Y-chromosome haplogroups showed a mix of African and West Eurasian lineages - including H2a, a European-centered mtDNA haplogroup not previously found in ancient African contexts, and Y-haplogroups on the E1b1b1 branch that originated in northeastern Africa about 25,000 years ago. The S and R cemeteries showed slight genetic differentiation, suggesting some isolation between island and mainland groups. And yet more recent work found no evidence that the two cemeteries represent different socioeconomic classes, as had previously been proposed. From the air, Kulubnarti is a long low island in a narrow black-rock gorge of the Nile - an unlikely, unremarkable-looking place that has produced some of the most detailed anthropological and genetic pictures of medieval Africa we have.