The wide tidal river mouth of the Chao Phraya river in Samut Prakan. Here, where the river flows into the Bay of Bangkok, i.e. the northern tip of the Gulf of Thailand (fig.), there are many sandbanks and bars called sandon (fig.).

This, at numerous places inundated, land is covered with mangrove (fig.) and nipa palms. These spits of land are in their own right home to several species of waterfowl, crabs and mudskippers (fig.).

To keep the estuary open for shipping it is continuously dredged by a fleet of large dredgers called reua khut (fig.).