Samut Prakan was built as a frontier town to protect the approach to Bangkok further up-river. Its importance grew due to its s tragic position at the river mouth. Walls were built along the river and forts were built at various locations. Many of these are now in a very dilapidated state or have been built over. However, a few remain in a good state and along the river bank on both sides are cannons left over from this period.

The six main forts are as follows:

  1. Phra Chulachomklao Fort (in good condition and open to the public)
  2. Plaeng Faifah Fort (now a park in Phra Pradaeng)
  3. Phi Sua Samut Fort (can be seen on the island between Paknam Market and Phra Samut Chedi)
  4. Nakarat Fort
  5. Phrakhonchai Fort
  6. Puchao Saming Phrai Fort

The following is a report of a visit to the Phra Chulachomklao Fort in June 1893, by Gustave Rolin-Jaequemyns, General Adviser to the King:

“For a long time we inspect the considerable work on the fort which, by its position, commands the river mouth and approximately a mile and a half of its course. There are seven brick towers, each equipped with a heavy caliber Armstrong gun. The masonry is completed. It only needs to be covered with a casing of earth and grass.

A mile into the sea there is a target on which they fire three shots with one gun and two with another. The charge of each shot is from 25 to 30 pounds of powder. The guns are hidden. They are hauled up by a hydraulic mechanism at the moment of the aiming and they disappear by themselves after the shot. The sight of this big, sly machine which ambushes and takes aim like a brigand to hide immediately thereafter, has something ferocious about it.”

The following month, on July 13th 1893, a skirmish took place between two French ships and the garrison manning the fort. Both sides suffered casualties. Although a smaller ship which was acting as a pilot boat for the French ships was badly damaged, the gun-ships still successfully bypassed the fort and other Thai gun-ships and made it up-river to Bangkok.