Why did the British navy blockade U.S. ports during the War of 1812?

During the War of 1812, the British navy utilized its overwhelming maritime superiority to impose a blockade on principal U.S. ports as a strategic measure to drive American shipping from the seas and curtail the nation's ability to trade.1

This action was the culmination of long-standing tensions stemming from the Napoleonic Wars. Britain sought to prevent the United States from supplying its enemy, France, and to protect its own commercial interests against American competition. The conflict was further fueled by the British practice of impressment, in which the Royal Navy accosted American merchant vessels to seize alleged deserters, often forcing U.S. citizens into British service.231

By blockading U.S. ports, Britain aimed to enforce its maritime policies, restrict the flow of war materials, and maintain its dominance over international trade routes, effectively treating the United States as a participant in the broader economic struggle against Napoleon.42