| Official Name: | Khlong San |
| Native Name: | คลองสาน |
| Native Name Lang: | th |
| Settlement Type: | Khet |
| Coordinates: | 13.7303°N 100.5097°W |
| Subdivision Type: | Country |
| Subdivision Name: | Thailand |
| Subdivision Type1: | Province |
| Subdivision Name1: | Bangkok |
| Subdivision Type2: | Seat |
| Subdivision Name2: | Khlong San |
| Subdivision Type3: | Khwaeng |
| Subdivision Name3: | 4 |
| Established Title: | District established |
| Area Total Km2: | 6.051 |
| Population Total: | 73263[1] |
| Population As Of: | 2017 |
| Population Density Km2: | 12107.59 |
| Timezone: | ICT |
| Utc Offset: | +7 |
| Postal Code Type: | Postal code |
| Postal Code: | 10600 |
| Geocode: | 1018 |
Khlong San (th|คลองสาน, pronounced as /th/) is one of the 50 districts (khet) of Bangkok, Thailand. On the west bank of Chao Phraya River, its neighboring districts across the river are (from north clockwise) Phra Nakhon, Samphanthawong, Bang Rak, Sathon, and Bang Kho Laem. On the west side of the river, the only land neighbor is Thon Buri district.
Khlong San is one of the oldest districts of Bangkok with a long history. Its name comes from the name of a khlong (คลอง; lit: canal) that runs through the area, "Khlong San" or "Khlong Prasan". Its starting from Chao Phraya River towards Khlong Somdet Chao Phraya Ong Noi at the front of Wat Phichai Yat connect with various canals were Khlong Wat Thong Thammachat, Khlong Wat Thong Nopphakhun, Khlong Lat Ya, all of which were canals that flow through the various orchards of the locals, the most famous fruit of Khlong San was longkong (a type of langsat). But about 70–80 years ago, there were excavations in various canals to build a road such as Lat Ya, Prajadhipok, Khlong San Roads or now's Somdet Chao Phraya Road.[2]
Khlong San was called, in chronological order, Amphoe Bang Lamphu Lang (บางลำภูล่าง), Amphoe Buppharam (บุปผาราม), and Amphoe Khlong San (since 1916) when it was part of Thonburi Province. Its status was changed to king amphoe in 1938 and back to amphoe again in 1957 due to population changes. It became part of Bangkok after the merging of Thonburi and Phra Nakhon Provinces in 1971.
Khlong San was originally the terminus of the Maeklong Railway, but the line was cut back to Wongwian Yai in 1961 to ease traffic congestion.[3]
The district is divided into four sub-districts (khwaeng).
| No. | Name | Thai | Area (km2) | Map |
|---|---|---|---|---|
| Somdet Chao Phraya | Thai: สมเด็จเจ้าพระยา | 1.317 | ||
| Khlong San | Thai: คลองสาน | 0.727 | ||
| Bang Lamphu Lang | Thai: บางลำภูล่าง | 2.234 | ||
| Khlong Ton Sai | Thai: คลองต้นไทร | 1.773 | ||
| Total | 6.051 | |||