[3] Quercus ellipsoidalis is a medium-sized deciduous tree growing to 20 meters (66 feet) tall with an open, rounded crown.

The acorns tend to be ellipsoid (ellipse-shaped, from which its scientific name derives), though they tend to be highly variable and range to globose, 6–11 millimeters (1⁄4–7⁄16 in) long and 10–19 mm (13⁄32–3⁄4 in) broad, a third to a half covered in a deep cup, green maturing pale brown about 18 months after pollination; the kernel is very bitter.

The inner surface of the acorn cap is glabrous (hairless) to sparsely or moderately pubescent, and the hairs if present tend to be kinky rather than straight.

[6] The morphological similarity between Q. ellipsoidalis and Q. coccinea remains a source of confusion, especially in northwestern Indiana and southern Cook County, Illinois.

[6][7] Northern pin oak is planted as an ornamental tree, popular for its bright red fall color and tolerance of infertile sandy soils.