High post is a basketball term used to describe an area on the court located at the top of the rectangular area and under the basket or the key.
This area is usually shaded and is marked with a semi-circle that is connected to the short side and marked just right at the opposite side of the basket.
It is named as such to distinguish it as the opposite of the low post, which is located at the bottom of the key.
This area is where the set-play usually begins. Many offensive players position themselves in this area to pick off or block a defensive player as well as lure them in to create scoring opportunities.
Defensive players, on the other hand, put themselves in this area to discourage offensive players from making their way to the basket.
Players, no matter their position, can act on the high post. There are also a number of play options for an offensive player in the high post as they are close enough to the basket to take a decent shot.
An offensive tactic that often utilizes the high post is the High Low Tactic, which sees one player placed in the high post and another player stationed in the low post.