Similar, but shorter, overland routes were the Mormon Trail (to Utah) and the Santa Fe Trail (to New Mexico). Other migration paths for early settlers prior to the establishment of the transcontinental railroads involved taking passage on a ship rounding the Cape Horn of South America or to the Isthmus (now Panama) between North and South America. There, a mule trek through hazardous swamps and rain forrests awaited the traveler which was quite arduous. A ship was typically then taken to San Francisco, California.
The Oregon Trail's generally designated starting point was Independence, Missouri along the Missouri River. The Oregon Trail's designated termination point was Oregon City, at the time the proposed capital of the Oregon Territory. However, many settlers branched off or grew exhausted short of this goal and settled at convenient or promising locations along the trail. Commerce with pioneers going further west greatly assisted these early settlements in getting established and launched local micro-economies critical to these settlements' prosperity.
The route of the Oregon Trail began to be scouted out as early as 1823 by fur traders and explorers. The trail began to be regularly used by fur traders, missionaries, and military expeditions during the 1830s. The first organized group of settlers headed west on the trail in 1841. On May 22, 1843 the first major wagon train on the Oregon Trail set out from Independence, Missouri with one thousand pioneers. Hundreds of thousands more would follow, especially after gold was discovered in California in 1849. The trail was still in use during the Civil War, but became obsolete in 1869 by the completion of the transcontinental railroad.
Pioneers on the Oregon Trail followed various rivers and used landmarks along the trail to guide their way and gauge their progress. Within Nebraska, the Oregon Trail followed the Platte River and then the North Platte River into Wyoming. Along this part of the journey, the Great Plains started giving way to bluffs and hills that were the precursor of the Rocky Mountains. Many rock formations became famous landmarks that Oregon Trail pioneers used to navigate as well as leave messages for pioneers following behind them. The first landmarks the pioneers encountered were in Western Nebraska, such as Court House Rock, Chimney Rock, and Scotts Bluff (where wagon ruts can still be seen to this day). Further west, in Wyoming, you can still read the names that these pioneers carved into a landmark bluff called Register Cliff.
The Oregon Trail was too long and arduous for the standard Conestoga wagons used in the Eastern U.S. at that time for most freight transport. These big wagons had a reputation of killing their oxen teams approximately two thirds along the trail and leaving their unfortunate owners stranded in desolate, isolated territory. The only solution was to abandon all belongings and traipse onward with the supplies and tools that could be carried or dragged. In one case in 1846 the Donner Party was stranded in the Sierra Nevadas in November and had to resort to cannibalism to survive.
This lead to the rapid development of the prairie schooner. This wagon was approximately half the size of the big Conestogas but was also manufactured in quantity by the Conestoga Brothers. It was optimized for the Oregon Trail's conditions and was a marvel of engineering in its time.
The map provided by this web site: http://www.endoftheoregontrail.org/maplibrary/oregontrail.html , and http://www.rootsweb.com/~orgenweb/1843trailmap.html make it clear that many settlers and pioneers also took this trail with the intention of branching prior to the Sierra Nevadas to southern territories such as Nevada or California.