Northern harriers are found throughout the northern hemisphere. In the Americas they breed throughout North America from Alaska and Canadian provinces south of tundra regions south as far as Baja California, New Mexico, Texas, Kansas, and North Carolina. They are only rarely seen breeding in parts of the Atlantic coastal states, such as Vermont, Rhode Island, and Maine and are similarly rare in the arid and mountainous western interior, including most of California, Oregon, and Washington. Their winter range is from southern Canada to the Caribbean and Central America.

In the Palearctic, northern harriers breed throughout Eurasia, from Portugal in the west, to Lapland and Siberia in the north, and east through China. They winter in northern African and tropical Asia.

Biogeographic Regions: nearctic (Native ); palearctic (Native ); oriental (Native )

Other Geographic Terms: holarctic