Samut Songkhram is one of the central provinces (changwat) of Thailand. Neighboring provinces are (from the south clockwise) Phetchaburi, Ratchaburi and Samut Sakhon. Local people call Samut Songkhram Mae Klong. The province is the smallest of all Thai provinces areawise. Chang and Eng Bunker, the famous Siamese twins were born here.
Samut Songkhram is located at the mouth of the Mae Klong river to the Gulf of Thailand. With several canals (khlong) the water of the river is spread through the province for irrigation. At the coast are many lakes for producing sea salt. The sandbar Don Hoi Lot at the mouth of the river is famous for its endemic shell population of Solen regularis.