The first major wagon train to the northwest departs from Elm Grove, Missouri, on the Oregon Trail.

Although U.S. sovereignty over the Oregon Territory was not clearly established until 1846, American fur trappers and missionary groups had been living in the region for decades, to say nothing of the Native Americans who had settled the land centuries earlier. Dozens of books and lectures proclaimed Oregon’s agricultural potential, piquing the interest of white American farmers. The first overland migrants to Oregon, intending primarily to farm, came in 1841 when a small band of 70 pioneers left Independence, Missouri. They followed a route blazed by fur traders, which took them west along the Platte River through the Rocky Mountains via the easy South Pass in Wyoming and then northwest to the Columbia River. In the years to come, pioneers came to call the route the Oregon Trail.

In 1842, a slightly larger group of 100 pioneers made the 2,000-mile journey to Oregon. The next year, however, the number of emigrants skyrocketed to 1,000. The sudden increase was a product of a severe depression in the Midwest combined with a flood of propaganda from fur traders, missionaries, and government officials extolling the virtues of the land. Farmers dissatisfied with their prospects in Ohio, Illinois, Kentucky, and Tennessee, hoped to find better lives in the supposed paradise of Oregon.

On this day in 1843, some 1,000 men, women, and children climbed aboard their wagons and steered their horses west out of the small town of Elm Grove, Missouri. The train comprised more than 100 wagons with a herd of 5,000 oxen and cattle trailing behind. Dr. Elijah White, a Presbyterian missionary who had made the trip the year before, served as a guide.

The first section of the Oregon Trail ran through the relatively flat country of the Great Plains. Obstacles were few, though the river crossings could be dangerous for wagons. As they traversed through Native American territories, the danger of attacks was a small but genuine risk. To be on the safe side, the pioneers drew their wagons into a circle at night to create a makeshift stockade. If they feared Native Americans might raid their livestock—the Plains tribes valued the horses, though generally ignored the oxen—they would drive the animals into the enclosure.

The pioneers quickly learned that they were more likely to be injured or killed by a host of other causes. Obstacles included accidental discharge of firearms, falling off mules or horses, drowning in river crossings, and disease. After entering the mountains, the trail also became much more difficult, with steep ascents and descents over rocky terrain. The pioneers risked injury from overturned and runaway wagons.

Yet, as with the 1,000-person party that made the journey in 1843, the vast majority of pioneers on the trail survived to reach their destination in the fertile, well-watered land of western Oregon. The migration of 1844 was smaller than that of the previous season, but in 1845 it jumped to nearly 3,000. Thereafter, migration on the Oregon Trail was an annual event, although the practice of traveling in giant convoys of wagons gave way to many smaller bands of one or two-dozen wagons. The trail was heavily traveled until 1884, when the Union Pacific constructed a railway along the route.