Throughout the eighteenth century the typical slave began his or her journey to Saint Louis from the middle Niger valley, over 600 miles to the east. The slave caravans first traveled overland under the command of slave merchants, who then directed the caravans either to the French slave markets of the upper Senegal, or to British slave ships waiting in the Gambia River. The slave caravans whose drivers headed for the upper Senegal moved toward the slave markets in the kingdom of Gajaaga, where a French fort marked the outer limits of the Atlantic trade networks under direct European control. By that time many of the slaves who had started the journey over a month before had died from exhaustion and hunger, and others had been sold off to African purchasers. Many of the slaves who survived to catch sight of the French fort had already been marched nearly 400 miles across the West African savanna.

The slaves who reached Gajaaga carried loads on their heads weighing fifty to sixty pounds. Caravans carried their own food and water, along with trade goods like ivory and gold dust. When there was nothing else to carry the slaves bore fifty to sixty pounds of rock, “so that extreme exhaustion would remove all desire to escape or to plot against those who drove them.” The largest slave caravans brought 200 slaves from the east, most of them destined to be sold to the French at Fort Saint Joseph, although others were purchased in the market towns by Soninke merchants and nobles, who needed slave labor to cultivate their fields, to weave cotton cloth, to mine gold, or to serve as attendants and household laborers.