Last name แม่น้ำ (Rivier 
, Maenam 
, แม่น้ำ) , globally, is quite a rare surname. The surname แม่น้ำ is habitual in Guadeloupe, where it is quite a common surname, Switzerland, where it is quite a rare surname, and France. Measured by absolute frequency, it is commonest in France, Switzerland, and the United States. Much less frequently, แม่น้ำ is the forename as well as the last name.