Abstract Under the leadership of two ordinary American men, a group of frontiersmen left St. Louis at the mouth of the Missouri River in 1804 and headed West to find a waterway to the great Pacific Ocean. In their journey west, they met several Indian tribes and learned their methods of survival. They collected samples of plants and animals and named bluffs, rivers and lakes. They documented their discoveries accurately and returned to share their knowledge with the American people and eventually with the rest of the world. Introduction The Purpose of my study is to acquaint myself and the readers with some of America’s earliest heroes and explorers who contributed to one of the major changes in the history of the United States. These men and woman called themselves “the Corps of Discovery” which is the most important expedition in the American history and the US first official exploration. It is also the start of a new young nation. In this paper, I will focus on the important factors that contributed to the success of the Corps of discovery such as establishing diplomatic relationships with the Native Americans and studying, understanding and respecting the different new cultures that they encountered. I will also discuss the great contributions of different women to the success of the Corps. These are the main aspects that have influenced the journey of this group and helped them meet their goals, successfully. I will also shed the light on these goals, the multiple accomplishments of the Corps of Discovery as well as on what could have contributed to their failures. History: In 1801, Thomas Jefferson became the president of the United States which then stretched from the Atlantic ocean to the lower half of the Mississippi river. At that time, the president understood the importance of expanding the US and establishing new water ways that connect the US to what he called “The Great Western Ocean” . In 1802, the president discussed his ideas and hopes with his secretary, Captain Meriwether Lewis, who would later be the leader for the Corps of Discovery across the American continent all the way to the Pacific Ocean (Tubbs, S. & Jenkinson, C., 2003). Also in 1802, the American president made an offer to Napoleon Bonaparte, the emperor of France, to buy New Orleans. It was a city owned by France and located at the mouth of the Mississippi river at the Southern border of the US at that time. He offered the emperor less than $10,000,000 for New Orleans which would be a strain to the US budget. Instead, Napoleon made a surprising counter offer and suggested to sell the entire Louisiana Territory to the United States for $15,000,000. The US quickly accepted that offer as it was the greatest land deal in history. Even though the US doubled its size overnight, a lot of people in the US were unhappy about what they called the “unaffordable purchase“. At that point, It was part of the mission of the Corps of Discovery to explore the newly purchased land in their way west (Ambrose, S. 1998). The Lewis and Clark Expedition was not only a military mission into the unknown and uncertain country, but it was also a scientific project founded by Thomas Jefferson, the president of the United States and funded by the congress of the United States (Tubbs & Jenkinson, 2003). January 18th, 1803. Confidential. Gentlemen of the Senate and of the House of Representatives. The river Missouri, & the Indians inhabiting it, are not as well known as is rendered desirable. It is however understood that the country on that river is inhibited by numerous tribes, who furnish great supplies of furs. From that moment on, the preparation for the journey began and Captain Lewis asked one of his friends, Lieutenant William Clark to join him in his trip to the Pacific ocean. William Clark accepted Captain Lewis’s offer and stated in a letter to him “my friend, I join you with hand and heart”. Even though according to several resources, these two gentlemen had different personalities, they had a great friendship which was a major factor in the success of the mission (Duncan, D. & Burns, K., 1997). The two Captains began their intense preparations for the trip in 1803 and finally began their trip Westward in May 1804. Apparently, prior to the beginning of the trip, Captain Lewis chose four dozen men who would change the course of history with him. They had to spend prolonged hours together practicing their roles and gaining knowledge that proved to be beneficial in their trip. They were a collection of hard working men with multiple skills which included blacksmiths, carpenters, tailors and hunters (Duncan & Burns, 1997). Captain Lewis studied information about the Indian cultures and languages. He also studied botany, zoology, medicine and celestial navigation. The men were multi taskers and had to possess multiple skills and strong personalities. They collected important items such as tools, compasses, map