Khlong San is one of the 50 districts, known as khet, located in Bangkok, Thailand. It is situated on the west bank of the Chao Phraya River.
The district shares borders with several neighboring areas across the river, including Phra Nakhon, Samphanthawong, Bang Rak, Sathon, and Bang Kho Laem. On the west side of the river, its only adjacent land neighbor is the Thon Buri district.