Final answer:
The "Oregon Fever" encouraged settlement in the Oregon Territory by promoting it as a land of opportunity and wealth, which was part of the broader Manifest Destiny ideology. It played an influential role in U.S. expansion policies, despite the challenges settlers faced upon arriving.
Step-by-step explanation:
The term "Oregon Fever" refers to the widespread enthusiasm in the mid-19th century United States for the settlement of the Oregon Territory, which was promoted as a region of great promise and potential wealth. Propaganda and guidebooks, such as the one by John C. Fremont, painted Oregon as a land of opportunity and wealth. This sensation contributed to the larger concept of Manifest Destiny and was a driving force behind the mass migration westward. Oregon was often described as having a pleasant climate and fertile soil, which lured thousands of Americans to move there, reinforcing the U.S. claim to the area.
In contrast to the rosy picture painted by Oregon Fever, the reality for many settlers included harsh conditions and difficulties. Despite the challenges, the promise of commercial possibilities in the Oregon Territory, including being a gateway for trade with Asia, made it a key objective for U.S. foreign policy. Annexing Oregon was seen as an essential part of national expansion and was related to both economic interests and national pride.