California TrailThe California Trail was an emigrant trail of about across the western half of the North American continent from Missouri River towns to what is now the state of California. After it was established, the first half of the California Trail followed the same corridor of networked river valley trails as the Oregon Trail and the Mormon Trail, namely the valleys of the Platte, North Platte, and Sweetwater rivers to Wyoming. The trail has several splits and cutoffs for alternative routes around major landforms and to different destinations, with a combined length of over .
American frontierThe American frontier, also known as the Old West, popularly known as the Wild West, encompasses the geography, history, folklore, and culture associated with the forward wave of American expansion in mainland North America that began with European colonial settlements in the early 17th century and ended with the admission of the last few contiguous western territories as states in 1912. This era of massive migration and settlement was particularly encouraged by President Thomas Jefferson following the Louisiana Purchase, giving rise to the expansionist attitude known as "Manifest Destiny" and the historians' "Frontier Thesis".
Oregon TrailThe Oregon Trail was a east–west, large-wheeled wagon route and emigrant trail in the United States that connected the Missouri River to valleys in Oregon. The eastern part of the Oregon Trail spanned part of what is now the state of Kansas and nearly all of what are now the states of Nebraska and Wyoming. The western half of the trail spanned most of the current states of Idaho and Oregon. The Oregon Trail was laid by fur traders and trappers from about 1811 to 1840 and was only passable on foot or on horseback.
Missouri RiverThe Missouri River is the longest river in the United States. Rising in the Eastern Centennial Mountains of the Bitteroot Range of the Rocky Mountains of Southwestern Montana, the Missouri flows east and south for before entering the Mississippi River north of St. Louis, Missouri. The river drains a sparsely populated, semi-arid watershed of more than 500,000 square miles (1,300,000 km2), which includes parts of ten U.S. states and two Canadian provinces.
