Opossums are members of the marsupial order Didelphimorphia endemic to the Americas. The largest order of marsupials in the Western Hemisphere, it comprises 120+ species in 19 genera. Opossums originated in South America and entered North America in the Great American Interchange following the connection of North and South America.
In the United States and Canada, the only species found is the Virginia opossum. It is often simply referred to as an "opossum", and in North America they are commonly referred to as possums (; sometimes rendered as 'possums in written form to indicate the dropped "o"). They should not be confused with the Australasian arboreal marsupials of suborder Phalangeriformes that are also called "possums" because of their resemblance to the Didelphimorphia. The opossum is typically a nonaggressive animal.
Opossums are found in North, Central, and South America. The Virginia opossum lives in regions as far north as Canada and as far south as Central America, while other types of opossums only inhabit countries south of the United States. The Virginia opossum can often be found in wooded areas, though its habitat may vary widely. Opossums are generally found in areas like forest, shrubland, mangrove, rainforest, eucalyptus forest etc. Opossums have been found moving towards north in recent years.