Explorer Zebulon PIKE was an American explorer and soldier who served in the United States Army during the early 19th century. He is best known for his exploration of the southwestern part of the United States and for leading two expeditions under the authority of the United States government. His first expedition, in 1806-07, was to explore the southern portion of the Louisiana Purchase. His second expedition, in 1810-11, was to explore the northern portion of the Louisiana Purchase and the Rocky Mountains. He also wrote several books about his explorations. PIKE's name is memorialized in several places, including PIKE's Peak in Colorado.