The three living genera of true geese are: Anser, grey geese, including the greylag goose, and domestic geese; Chen, white geese (often included in Anser); and Branta, black geese, such as the Canada goose.
Fossils of true geese are hard to assign to genus; all that can be said is that their fossil record, particularly in North America, is dense and comprehensively documents many different species of true geese that have been around since about 10 million years ago in the Miocene.