Abstract: This paper examines the historical context of census-taking and its importance to development trajectory of Nigeria from 1866 to 2006. Secondary data obtained from five-year national development plans, archival records, in-depth interviews and extant demographic literature were used to determine how population census exercises has evolved in a 140-year period, the problem of counting Nigerians living in Nigeria, and the politics of using population as a yardstick for distributing national wealth. The study shows that nearly all censuses were found to be grossly inadequate, tradition of conducting censuses every ten years has not taken root in Nigeria, and colonial administration as well as post- independence governments grappled with politics of numbers for socio-economic development planning. Despite flaws, the 1991 census remains relatively acceptable amidst fifteen complete and incomplete censuses ever taken in Nigeria in the period under study. Key words: Census, Development, de Facto