The primary reason for the start of the War of 1812 was the ongoing maritime disputes between the United States and Great Britain. These disputes included issues such as the impressment of American sailors into the British Navy, interference with American shipping, and British support for Native American resistance against American expansion. Tensions escalated as the U.S. sought to assert its sovereignty and protect its maritime rights. The war officially began on June 18, 1812, leading to significant battles and the eventual recognition of U.S. independence and rights.