The PhD thesis evaluates the socio-political effects of land alienation (i.e., the removal of at least some of the rights of previous users) on states and populations in sub-Saharan Africa in the 21^st century. Using satellite imagery and various georeferenced data, I estimate proximity, spillover and temporal effects. First, I investigate how state power and large-scale land acquisitions interact with each other. Second, in collaboration with other academic researchers, we estimate the impacts of large-scale land acquisitions on social trust. Next, we investigate how land alienation impacts the likelihood of conflicts involving pastoralist societies in the Sahelian region. Finally, through a case study of Uganda, I look at whether land alienation has an impact on land tenure security and individual land titling. Altogether, my PhD thesis shows that land alienation has widespread impacts on African societies and their states, creating situations typical of a ‘frontier’.