The British claimed North America during the Age of Exploration. Once Italian sailor Christopher Columbus sailed west for Spain and made it to the Bahamas (even though he mistakenly thought he was off the coast of China), other explorers and sailors were encouraged to sail west to claim lands for European nations. Italian explorer John Cabot, who sailed for England, explored the New England coastline in 1497. He mistakenly thought it was Asia, but claimed the land for England. Later, in 1585, the British make their first attempt at colonization on the island of Roanoke. This settlement failed, and their first permanent settlement was at Jamestown, Virginia in 1607.
Later in the 18th century, English explorer James Cook set out to find the fabled Northwest Passage, a waterway that would connect the Atlantic and Pacific islands. While he didn't find the Northwest Passage (because it doesn't exist!), he found the western coast of the United States. Later, two men named Lewis and Clark were commissioned to explore this territory, and the British challenged Spanish rule over the area.