Tamsui is located near the outlet of the Tamsui (Danshui) River into the Taiwan Strait. Originally home to Formosan indigenous peoples, Tamsui was next settled by the Spanish in 1629 as the town and mission of San Domingo. The Spanish were expelled by the Dutch in 1641, who built Fort Anthonio, forming what is known today as Hongmao Castle. Following the departure of the Dutch in 1661, Tamsui continued to grow, becoming the largest port in Taiwan by the 19th century. By the 20th century, accumulation of silt in the river forced most port operations to move further north to Keelung. Due to its close proximity to Taipei City, Tamsui has become a favorite destination for city dwellers to take a stroll and enjoy a coffee along the riverside.