 The northern half of North America is sparsely populated and covered mostly by Canada, except for the northeastern portion, which is occupied by Greenland, and the northwestern portion, which is occupied by Alaska, the largest state of the United States.The central and southern portions of the continent are occupied by the contiguous United States, Mexico, and numerous smaller states in Central America and in the Caribbean.The continent is delimited on the southeast by most geographers at the Darién watershed along the Colombia-Panama border, placing all of Panama within North America.