After passing Chiang Mai, it flows through the provinces of Lamphun, Tak and Kamphaeng Phet.

At the confluence with the Nan at Nakhon Sawan (also named Paknam Pho in Thai), it forms the Chao Phraya River.

Mengrai, a ruler and conqueror from Xishuangbanna, turned south to create an alternative "silk road" along the Ping River itself and captured Haripunchai in 1281.

Chinese and foreign investors flooded the area, all in search of lucrative teak and business transactions.

With no cure for leprosy until the 1980s, lepers found relief in their sanctuary from social criticism, many of whom remain at the McKean Rehabilitation Centre today.