Colonial practices of ethno-racial segregation impacted grievously on conflict and state building in Nigeria. While such practices have continued to undergird postcolonial contexts of institutional fragility and state weakness, their impacts are yet to be accounted for in the literature on economic and political development in Africa. This article examines the colonial constructions of Fulani, Hausa and other groups ethnically not indigenous to Yorubaland as migrants and minorities, through their denial of land rights; dispossession and marginalization using customary law, indirect rule and other institutionalized instrumentalities of the colonial ethnographic state. It accounts for the continuing impacts of such struggles over land for citizenship, state fragility, state weakness and the forging of nationhood in Nigeria. How have colonial constructions of the customary affected resource-based conflict and postcolonial conceptions of citizenship and inter-ethnic relations? Drawing on archival and ethnographic data generated in Yorubaland, Nigeria, on the conflict between Hausa-Fulani migrant pastoralists and indigenous Yoruba agriculturalists over land, this work underlines how the struggles over agricultural resources, governance, land and political power have continued to affect the manner in which political authority is constituted in colonial and postcolonial Nigeria.