Ujiji is the oldest town in western Tanzania and is located in Kigoma-Ujiji District of Kigoma Region. Originally a Swahili settlement and then a…Ujiji is the oldest town in western Tanzania and is located in Kigoma-Ujiji District of Kigoma Region. Originally a Swahili settlement and then an Arab slave trading post by the mid-nineteenth century nominally under the Sultanate of Zanzibar, the town is the oldest in western Tanzania. In 1900, the population was estimated at 10,000 and in 1967 about 41,000. The site is a registered National Historic Site.