Mailiao Harbor is located at Mailiao area of the offshore Primary Industry Zone in Yunlin County. The Yunlin offshore Primary Industry Zone is a project planed by the Ministry of Economic Affairs and based on the national development of primary industry to co-op with the land necessity of the construction and relocation of the Sixth Naphtha Cracking Business, is planed to develop the industrial zone by way of dredging sea sands for the landfill to create offshore lands.