Noso, located at the northern shore of the confluence of three rivers, Kizu-gawa River (Kyoto Prefecture), Katsura-gawa River (Yodo-gawa River system) and Seta-gawa River, where the castle was built and which was a natural fort surrounded by rivers on three sides, was a major urban area of the old commercial district, 'Yodo.'
納所は木津川(京都府)・桂川(淀川水系)・瀬田川の三川が合流するポイントの北岸にあたりに築城され、三面を川に囲まれた天然の要害で、古くからの商業地「淀」の中核都市であった。