Dissertation (Master of International Relations)This study assessed the interface among local-level government institutions and their collective influence in curbing illegal migration in Tanzania, with Ngara District as a case study. The study examined the magnitude of illegal migration in Tanzania, and the extent of collaboration among local-level government institutions over illegal migration. In addition, the study evaluated the effectiveness of regional administration to coordinate efforts in mitigating illegal migration while assessing the willingness of other local-level government actors to support regional administration. Furthermore, it examined the methods used by local-level government institutions to prohibit illegal migrants and unravel the challenges experienced by the local-level government institutions in curbing illegal immigration in Tanzania. Data were collected from Ngara District council, civil society organization, some villages and migration office sampled from wards in the District, through qualitative and quantitative procedures, i.e. focus group discussion, face-to-face interviews and observation. A total of sixty-two (62) informants were sampled using both purposive and random sampling techniques to provide the information needed for the study. The extent of collaboration among local-level government institutions over illegal migration was found to be moderate. The effectiveness of regional administration to coordinate efforts in mitigating illegal migration was low while the willingness of non-government actors to support regional administration was found to be high. Local leadership were found not effective in curbing the issue of illegal immigrants in Ngara district while the methods used by local leadership to prohibit illegal migrants in Tanzania could not support the proposed measures to mitigate illegal immigrants. In the light of the findings, therefore, the study recommends that measures to enhance the capacity of regional administration and local-level government institutions to address the problem of the illegal flow of immigrants ought to undertake should be taken. But also civic education on policy and migration matters to local institutions to curb illegal immigration in Tanzania should be given. The other recommendation includes a review of migration policies which seem to be loose and with gaps that could not effectively prohibit illegal immigrants.