Pom Maha Kaan, or Mahakan Fort, is an octagonal, 3-storey stronghold along Khlong Rop Krung, the city canal at the edge of Rattanakosin, the historical part of Bangkok.

It is 38 meters wide, 35 meters high, and is surrounded by a 4,9 meter high wall. It has a two-tiered, cone-shaped roof, which is said to look like an inverted lotus leaf. There are a total of 6 canons in the battlement cavities.