Blockade Law and Legal Definition

Blockade means the isolation of a nation, area, city, or harbor by hostile ships or forces in order to prevent the entrance and exit of traffic and commerce.

Blockade as used in International law refers to a belligerent's prevention of entry to or departure from an enemy's ports by stationing ships to intercept vessels trying to enter or leave those ports. In order to be binding a blockade must be effective. The government of the United States has uniformly insisted that the blockade should be effective by the presence of a competent force, stationed and present, at or near the entrance of the port. It must be maintained by a force sufficient to prevent access to ports. Blockades are regulated by international law and custom, which require advance warning to neutral states and impartial application. Penalties for breach of blockade are seizure of ship and cargo and their possible condemnation as lawful prizes. Usually, neutral ships may not be destroyed for blockade running.