Thonburi is one of the 50 districts (khet) of Bangkok. On the west bank of the Chao Phraya River, it was once part of Thon Buri Province. Neighbouring districts are (from north clockwise) Bangkok Yai, Phra Nakhon (across Chao Phraya River), Khlong San, Bang Kho Laem (across Chao Phraya), Rat Burana, Chom Thong, and Phasi Charoen.
In addition to the native inhabitants, the district was settled relatively early by foreigners, first Chinese merchants, then the Portuguese after the fall of Ayutthaya to the Burmese in 1769. In addition to the Chinese and Portuguese, there were also Muslims and Mon, from Burma, as well as French priests, particularly in the neighbourhood called Kudi Chin. The area still retains many Chinese shrines, mosques, and Santa Cruz Church, the second Catholic church to be built in Thailand.
The district used to be called Amphoe Ratchakhrue due to a nearby wat of the same name. It was renamed Amphoe Bang Yi Ruea on 11 July 1916 (after the location of the new amphoe office), and finally to Thon Buri on 17 April 1939. The district then belonged to Thon Buri Province. In December 1971 the province was merged with Bangkok to form the present day Bangkok metropolitan area.
The district is divided into seven sub-districts (khwaeng): Wat Kanlaya, Hiran Ruchi, Bang Yi Ruea, Bukkhalo, Talat Phlu, Dao Khanong and Samre.
Places of interest include Santa Cruz Church, Wat Kanlaya, Wat Intharam and Wat Bang Yi Ruea.
Wongwian Yai is a major bus hub on the west side of the Chao Phraya River whileThe district is served by Bangkok Skytrain stations: Pho Nimit, Talad Phlu and Wutthakat.