Tianjin and Nakhon Sawan are friendly associated on October, 11th,  in 2002.

Nakhon Sawan is a city in Thailand, the name literally means "Heavenly City". The city is the capital of Nakhon Sawan Province, and covers the complete subdistrict Pak Nam Pho and parts of Khwae Yai, Nakhon Sawan Tok, Nakhon Sawan Ok and Wat Sai, all of Mueang Nakhon Sawan district. As of 2007 it has a population of 125,000.

Nakhon Sawan is about 240 kilometres north of Bangkok, and marks the point of confluence of two of Thailands major rivers, the Ping and the Nan. These converge in Nakhon Sawan to form the Chao Phraya which flows south to Bangkok and out into the Gulf of Thailand.

Bueng Boraphet located east of Nakhon Sawan is Thailand's biggest freshwater swamp.