The Northern red oak, Quercus rubra (Quercus borealis in some older references), is an oak in the red oak group (Quercus section Lobatae). It is a native of North America, in the northeastern United States and southeast Canada. It grows from the north end of the Great Lakes, east to Nova Scotia, south as far as Georgia and northern Alabama, and west to eastern Kansas. It favors mesic or moderately moist valley and hillside sites with good soil that is slightly acidic. Northern red oak is so named to distinguish it from Southern red oak, also known as the Spanish oak.

In forests, the Northern red oak grows straight and tall, to 35 m, exceptionally to 43 m tall, with a trunk of up to 1 m diameter; open-grown trees do not get so tall, but can develop a stouter trunk, up to 2 m diameter.

Northern red oak is easy to recognize by its bark, which features bark ridges that appear to have shiny stripes down the center. A few other oaks have bark with this kind of appearance in the upper tree, but the Northern red oak is the only tree with the striping all the way down the trunk.

The leaves are 12-25 cm long, with 7-11 lobes; the lobes are bristle-tipped, and less deeply cut than most other oaks of the red oak group (except for Black oak which can be similar). The acorns are borne in a shallow cup 2 cm wide, have a flat base and acute apex, 12-20 mm long, green, maturing nut-brown about 18 months after pollination. Despite their bitter kernel, they are eaten by deer, squirrels and birds.

The largest Northern red oak recorded used to be in Ashford, Connecticut. The tree has since suffered falling limbs because of its great age. However this tree is still a sight to behold; the trunk is huge, 8 meters (26 feet) in girth, and the root-knees impressive. The oak is located on Giant Oak Lane off U.S. Highway 44. There are several other large oaks in the area.

Northern red oak is the state tree of New Jersey.

Cultivation and uses

It is one of the most important oaks for timber production in North America. The wood is of high value. Other related oaks are also cut and marketed as red oak, although their wood is not always of as high a quality. These include Black oak, Scarlet oak, Pin oak, Shumard oak, Southern red oak and other species in the red oak group. It has been widely introduced outside of its range, and is listed as an invasive species in some parts of Europe.