Gorontalo is one of the areas around Tomini bay which is the place used for fighting in the surrounding kingdoms (Ternate, Tidore, Palasa, Bugis, Makassar), againts the Netherlands. In addition, the Gorontalo region was targeted by the Mindanao (Mangindano) and Galela pirates who controlled the waters of Tomini Bay. To deal with these attacks, three fortresses was built at the opening of the Bone Bolango River overlooking Tomini Bay in different period. The location is very strategic and became the main gateway to Gorontalo from the sea. This study aims to determine the development of the fortress in Gorontalo, role and function in each period. The research method used is historical archeology, which combine archeological data with written sources. The results showed that there were three periods of fortification construction in Gorontalo, namely; the Sultan Botutihe period, the VOC period, and the Dutch East Indies colonial period which had different character and function.