Ukerewe District is one of the seven districts of the Mwanza Region of Tanzania. It is located on Ukerewe Island, Ukara Island and other neiā¦Ukerewe District is one of the seven districts of the Mwanza Region of Tanzania. It is located on Ukerewe Island, Ukara Island and other neighbouring islands within Lake Victoria. The largest settlement and the district's administrative capital is Nansio.