Khlong Chong Nonsi

Khlong Chong Nonsi and its public park in 2021.

Khlong Chong Nonsi (Thai: คลองช่องนนทรี, pronounced [kʰlɔ̄ːŋ t͡ɕʰɔ̂ŋ nōn.sīː]) is a khlong (canal) in Bangkok's economic and financial district as well as the nearby Khlong Sathon.

Khlong Chong Nonsi runs from Surawong road all the way down to the Chao Phraya river. It covers a distance of 4.5 km (2.8 mi) through districts of Bang Rak, Sathon and Yan Nawa. It is also the origin of the name Chong Nonsi. One of the two khwaengs (sub-district) in Yan Nawa district, where it empties into the Chao Phraya river. Currently, it runs parallel to the entire length of Narathiwat Ratchanakarin road. Somephases it crosses with other roads such as Chan, Rama III. The BTS SkyTrain Silom Line is at the northern end and the BRT bus runs up and down most of the canal. The width of the mouth of the canal is about 20 m (65.6 ft), and the phase runs along Narathiwat Ratchanakarin road is about 6 m (19.7 ft)–8 m (26.2 ft) wide.

Its name "Chong Nonsi" is believed to be distorted from the word "Chong Nang Ni" (ช่องนางหนี) which means "a channel that lady escaped". It comes from a folklore titled "Legend of Lord U Thong", the story about an Ayutthaya mythical king named U Thong, who escaped cholera to various places and gave rise to the names of different places later on.

A 2018 survey found that Khlong Chong Nonsi, especially the intersection of Silom and Surawong roads, was the dirtiest in Bangkok.

Chong Nonsi Canal Park

Main article: Chong Nonsi Canal Park

On December 25, 2021, the Chong Nonsi Canal Park was opened by Bangkok Metropolitan Administration (BMA). It is the first phase of the Khlong Chong Nonsi restoration project with a distance of 200 m (656.2 ft) from the total project distance of 4.5 km (2.8 mi). The construction period is divided into four phases.