Wichai Prasit Fort is situated in a strategic location known as the "Gateway to the Capital," controlling the main navigation route of the Chao Phraya River. During the Ayutthaya period, this fort served to intercept foreign merchant and warships, preventing easy access to the royal capital. A key feature was the presence of twin forts on opposite banks, capable of stretching a massive iron chain across the river to halt enemy vessels. Its position at the mouth of the Bangkok Yai Canal allowed for comprehensive and highly effective monitoring of all maritime movements.