Why were early settlers said to have Oregon fever?

Early settlers experienced "Oregon fever" due to the allure of fertile land, economic opportunities, and the promise of a better life in the Oregon Territory. Reports of abundant resources, mild climate, and the potential for farming attracted many families seeking to escape overcrowded and economically depressed areas in the East. The discovery of the Oregon Trail and the promotion of westward expansion by figures such as John C. Frémont further fueled this enthusiasm, leading thousands to embark on the arduous journey westward in the mid-1800s.