The largest and possibly most significant Swahili site in Tanzania is Tongoni, which is located 25 km north of the Pangani River.

Overlooking Mtangata Bay, about forty standing tombs and a Friday mosque of the "northern" style occupy a third of a hectare.

Tongoni, the village of Mtangata, and its about 3,500 inhabitants, most of whom are cassava and coconut farmers and fishermen, are surrounded by scattered trees (baobabs, tamarinds, and palms).

[5] On a Pleistocene terrace that overlooks Mtangata and the ocean vastness to the east, residents of the wider countryside, including those who self-identify as Zigua, Digo, and Nyamwezi (the latter being recent migrants), produce maize and vegetables and gather firewood.

Group D is a form of pottery with raised dots that is known from the East Usambara Mountains and dates to the middle to late second millennium C.E.

[7] Additionally, one STP located west of the mosque produced a piece of gneiss grindstone, a raw material found only nearby mountains.

At Vumbani, a subsurface test turned up bits of Indian ceramics, Chinese celadon, blue-green Islamic monochrome, and coiled and drawn glass beads.

[10] One unusual stone of unknown material, two smoothed sharpening stones, a group of coral fragments partially encircling an ash pit, huge local sherds (many decorated), one blue glass bead, one faceted carnelian tube bead, and an oyster nut seed are among the special discoveries.

The carved face , the faceted carnelian bead that Zigua healers have worn in the past, and the oyster nut seeds all have intriguing meanings.

Even though this collection only represents a small portion of an excavation, differences in the character and abundance of various vessel forms, fish and non-fish bones, shellfish, and particular artefact types show that Tongoni has changed over time.

For the majority of the time that Tongoni was inhabited, people lived in wattle-and-daub houses to the west and northwest of the main coral ruins.

Tongoni may have had the chance to escape Mombasa, its northern neighbour, for a while by an eventual alliance with foreign invaders, the Portuguese.

Foreign objects were discovered during inspections and excavations in low-lying Swahili sites like Tongoni along the Pangani River region, including glass beads and early Middle Eastern pottery like hatched sgraffiato.

The majority (80%, n = 44 of 55) of the beads at Kumbamtoni (Site 52a) are fashioned of marine mollusk shell, not glass, in contrast to Muhembo and Tongoni.

Swahili bowls were also decorated by riverine inhabitants using graphite from the Usambara Mountains (e.g., Kumbamtoni, Site 52a, Excavation Unit 2).

Unlike Mombasa, the majority of coastal communities in the western Indian Ocean experienced a decline in population, influence, or even total collapse.

Unique artefacts and higher shellfish consumption in the area suggest that locals tried to change their way of life and develop coping mechanisms (e.g., Tongoni, Excavation Unit 3, levels 5-7).

Examples of hinterland ceramics from this time period can be found at sites along the coast, including Group D (at Tongoni, Excavation Unit 2) and a rouletted tradition that is probably from western Tanzania.

[22] The nineteenth century saw an increase in the worldwide traffic in slaves and ivory as well as the influence of Omani (and European) plantation agriculture, which amplified the pressures from earlier eras.

Swahili-speaking patricians working in these circumstances were influenced by changes in the culture and economy to further set themselves apart from hinterland "pagans" (non-Muslims), in part by exaggerating tales about foreign origins.