Muscovy Duck commonly is kept in captivity, and feral populations and free ranging domestic type Muscovies now occur well outside its original range, which extends from extreme southern Texas and northern Mexico south to northern Argentina. In Mexico, Muscovy occurs on both slopes:, north along the Gulf coast to northern Tamaulipas and central Nuevo Leon (Cruz-Nieto 1991, Whitley 1973, Rojas 1954). It is rare in the Yucatan Peninsula, but common in Belize southward through the remained of Central America (Bolen 1983). On the Pacific slope its distribution extends from southern Sinaloa in Mexico south through Panama (Wetmore 1965). Muscovy Duck is very local on the Pacific slope of South America, where it is reported from western Colombia in northern Chocó and Nariño (Hilty and Brown 1986), and in southwestern Ecuador in Guayas (Ridgely and Greenfield 2001a). Its distribution is more continuous in the lowlands north and south of the Andes, where it is widespread (Gomez-Dallmeier and Crigan 1989, Haverschmidt 1968), south to northern Argentina.
Perhaps the largest established feral population of Muscovy Duck is in Florida, southeastern United States (Robertson and Woolfenden 1992, Pranty et al. 2006).
Muscovy Duck is considered resident across most of its range, but at least locally, as in Venezuela, it has "marked local and seasonal migratory movements" (Hilty 2003).
Muscovy Duck strictly occurs in the lowlands, with upper elevational limits of 1200 m in Mexico (Howell and Webb 1995), mostly below 500 m in Colombia (but wandering to as high as 2600 m; Hilty and Brown 1986), to 300 m in Venezuela (Hilty 2003) and in Ecuador (Ridgely and Greenfield 2001a), and to 600 m in Bolivia (Hennessey et al. 2003).