Bigo

Bigo, also Bigo bya Mugenyi, is an extensive alignment of ditches and berms comprising ancient earthworks located in the interlacustrine region of southwestern Uganda. Situated on the southern shore of the Katonga River, Bigo is best described as having two elements. The first consists of a long, irregular ditch and bank alignment with multiple openings that effectively creates an outer boundary by connecting to the Kotanga River in the east and the Kakinga swamp to the west. Toward its eastern end the outer ditch branches further to the east to encompass a nearby crossing of the Katonga River. The second element consists of a central, interconnected group of four irregularly shaped ditch and bank enclosures that are connected to the Katonga River by a single ditch. Three mounds are associated with the central enclosures; two within and one immediately to the west. When combined, the Bigo earthworks extend for more than 10 kilometers. Resulting from radiometric dates collected from archaeological investigations conducted in 1960 and additional investigations undertaken at the Mansa earthworks site in 1988, 1994, and 1995, the Bigo earthworks have been dated to roughly AD 1300-1500, and have been called Uganda's "largest and most important ancient monument."

Bigo was first documented in 1909; initially by Colonial District Commissioner D. L. Baines and then followed by Major C. R. Hall who also completed the first map of the earthworks. A more comprehensive map of the earthworks was completed for the Uganda Protectorate Geological Survey by A. D. Combe in 1921. Following this, P. L. Shinnie excavated a series of trenches at Bigo in 1957 in order to investigate the purported connections between Bigo and Bacwezi legends as well as to identify the material culture of the people who built the earthworks.

In the fall of 1960, M. Posnansky conducted further investigations at Bigo with the intent to "make as complete a survey as possible ... to establish the cultural sequence [of the site] and to obtain charcoal samples for Carbon 14 dating." During his investigation of Bigo, Posnansky spent over 7 weeks excavating more than 20 trenches (with a total volume of 781 cubic feet) at four locations (three within the main enclosure area and one at the outer ditch). From these trenches Posnansky prepared sidewall illustrations characterizing the site's soils and exposing the construction history of the mounds and ditches. Also recovered from the trenches were four charcoal samples that were submitted for radiometric dating and over 4,200 pottery sherds.

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