Assin Manso Slave Market. Assin Manso is located 40km from Cape Coast along Cape coast Kumasi highway. There are prominent signboards and visitor centre to be found on the east side of the highway as you enter the town. Trained tour guides are there to take visitors round. Assin Manso was the final link in the key slave route from Northern Ghana and was known to have been the largest slave market for merchants supplying slaves to the forts and castles on the coast