The event that sparked tensions leading to the War of 1812 was the ongoing maritime conflicts and trade restrictions imposed by Britain on American shipping. British interference, including the practice of impressment—forcing American sailors into the Royal Navy—created significant resentment in the United States. Additionally, the British support of Native American resistance against American expansion in the Northwest Territory heightened tensions. These grievances ultimately led to the declaration of war in 1812, as the United States sought to assert its sovereignty and protect its economic interests against British interference.