A buckeye nut is a nut-like seed from a buckeye tree. The nuts are typically ¾ inch to 1 inch in diameter and are poisonous to humans and livestock.
Buckeye nuts are produced from the species Aesculus glabra. The trees flower in spring and produce a round, inedible fruit. Each fruit contains one to three seeds that are predominantly brown with a whitish circular spot. Buckeye trees are primarily found in the lower Great Plains and the Midwest, but they may also be seen in small groves in the South. The trees generally reach heights between 49 and 82 feet.