Mueang Tha Chin name was firstly found in Ayutthaya law that refer to the governor position, Phra Samut Sakhon. The city was managed into the southern cities group that controlled by the Defence ministry. King Mahachakkraphat ordered to establish Mueang Sakhon Buri. King Mongkut (Rama IV) changed the city name to be Samut Sakhon. In 1897 Mueang Samut Sakhon was changed status to be Mueang Samut Sakhon district.

Local Thai people always calls Mueang Samut Sakhon district in the name Maha Chai.

Samut Sakhon was formerly called "Tha Chin" probably because, in the old days, it had been a trading port dealing with a vast number of Chinese junks. ln 1548, a town named "Sakhon Buri" was established at the mouth of the Tha Chin River. It was a centre for recruiting troops from various seaside towns. The name of the town was changed into "Mahachai" when Khlong (canal) Mahachai was dug in 1704 to join the Tha Chin River at the town. Later, the town was renamed "Samut Sakhon" by King Rama IV but it is still popularly called "Mahachai" by the villagers. Samut Sakhon occupies a total area of 872 square kilometres;