The institution of Aku Uka is one of the traditional political systems mandated with the power of steering Kwararafa Confederate State (which later metamorphosed into Jukun Kingdom) from the pre-colonial period to date. The Jukun of Kwararafa and the Aku as their head now live in some scattered settlements along the middle reaches of River Benue with headquarters at Wukari. Although, they are not very numerous today, they played considerable roles in the history of central and northern Nigeria in the past, and exercised lasting influences on many of their neighbours. The Aku Uka, like any other traditional ruler, was the major actor or bedrock of nation building. Even with the advent of British Colonial administration, his institution remained one of the major actors playing very fundamental and indispensable roles in nation building. Nevertheless, there are some challenges confronting the institution. In spite of the British colonization and subsequent creation of states and local government areas, the Aku still maintained his influence and authority in the Middle Belt region. Thus, the main concern of this paperis to explore into an in-depth historical analysis on the origin and history of Aku Uka, the roles it plays in nation building and some of the challenges confronting the institution in the 21st Century. The methodology used in carrying out the research was mainly based on the critical consultation and evaluation of primary and secondary sources. Key words: Aku Uka, Nation Building, Challenges, Sangari..