- Missionary Work: Whitman was a medical missionary who, along with his wife Narcissa, traveled to the Oregon Country in 1836 under the auspices of the American Board of Commissioners for Foreign Missions (ABCFM). Their mission was to establish a Protestant mission among the Native American tribes of the region. They set up the Whitman Mission, which became a crucial waypoint for settlers traveling along the Oregon Trail.
- Medical Services: As a medical doctor, Whitman provided medical care not only to the Native American communities but also to the increasing number of settlers arriving in the Oregon Country. His medical skills and knowledge were invaluable, especially in remote areas where access to medical care was scarce.
- Negotiations: Whitman played a pivotal role in negotiating with Native American tribes, particularly the Cayuse, during times of tension. His influence and diplomatic skills helped maintain peace and cooperation between settlers and Native Americans, although ultimately conflicts did arise.
- Oregon Trail Guide: In 1843, Whitman returned to the eastern United States and led a significant group of settlers, known as the "Great Migration," back to the Oregon Country. He provided guidance, advice, and support to the travelers throughout the arduous journey along the Oregon Trail. His knowledge and experience contributed to the success of the migration.
- Political Advocate: Whitman engaged in political advocacy and lobbied for the establishment of a government in the Oregon Country. He helped lay the groundwork for the provisional government of Oregon, which aimed to establish law and order in the rapidly growing region.
- Exploration: Whitman's explorations and surveys of the Oregon Territory expanded geographic knowledge of the region. He documented his observations and shared them with others, providing valuable information for future expeditions and settlements.
- Cultural Exchange: Whitman's mission work brought him into close contact with Native American communities, and he played a role in facilitating cultural exchange and understanding between Native Americans and settlers.
Overall, Marcus Whitman's contributions as a missionary, medical practitioner, diplomat, trail guide, political advocate, explorer, and cultural mediator made him a significant figure in the early history of the Pacific Northwest and the development of the Oregon Territory.