A number of species of Odonata in south-eastern Nigeria have not been seen for decades, while others have not been recorded since their description. The Mango River in the Oban division of the Cross River National Park (CRNP) in eastern Nigeria was visited three times every month in September 2019, January and March 2020, to survey species of Odonata. The survey was carried out with a view to rediscovering lost species or species that are hitherto not known to occur in the study area. Micrographs of the thorax and wings of specimens suspected to be relict species of Odonata were taken and compared with data in literature to determine their actual identities. A total of 61 individuals of Odonata belonging to 34 species in nine families were collected. Of the 34 species, three, Africocypha lacuselephantum (Vulnerable), the relict Pentaphlebia stahli (Vulnerable) and Umma purpurea (Endangered) are new records for Nigeria. This record of rare and common species provides a preliminary baseline data for a checklist of the Odonata fauna in Oban Hills for possible formulation of conservation strategies for threatened species in the area in particular and south-eastern Nigeria at large.