He worked hard for the Platte Purchase, which extended the northwestern boundary of Missouri to the Missouri River in 1837.

In 1843, Rufus Sage, an explorer and experienced observer recorded jaguar present on the headwaters of the North Platte River 30 – 50 miles north of Long's Peak in Colorado.

) After the rail line's initial steep climb through the bluffs of west Omaha and out of the Missouri River Valley, the route followed the Platte River west through Nebraska, establishing many townships along the way ( Elkhorn, Grand Island, North Platte, Ogallala, Sidney, Nebraska ), the Colorado Territory ( Julesburg ), the Wyoming Territory ( Cheyenne, Laramie, Green River, Evanston ), the Utah Territory ( Ogden, Brigham City, Corinne ), and connecting with the Central Pacific at Promontory Summit.

* " central route ", to avoid the worst of the Rocky Mountains by following the Platte River in Nebraska and the South Pass in Wyoming, much of the path of the Oregon Trail, or

Through Nebraska it followed the Great Platte River Road, cutting through Gothenburg, Nebraska and passing Courthouse Rock, Chimney Rock, and Scotts Bluff, clipping the edge of Colorado at Julesburg, Colorado, before arriving at Fort Laramie in Wyoming.

From various " jumping off points " in Missouri, Iowa or Nebraska Territory, the routes converged along the lower Platte River Valley near Fort Kearny, Nebraska Territory and led to rich farmlands west of the Rocky Mountains.

The party continued east via the Sweetwater River, North Platte River ( where they spent the winter of 1812 – 1813 ) and Platte River to the Missouri River, finally arriving in St. Louis in the spring of 1813.

Trying to transport their extensive fur collection down the Sweetwater and North Platte River, they found after a near disastrous canoe crash that the rivers were too swift and rough for water passage.

They normally used the north side of the Platte River — the same route used 20 years later by the Mormon Trail.

" In 1830, William Sublette brought the first wagons carrying his trading goods up the Platte, North Platte, and Sweetwater River ( Wyoming ) before crossing over South Pass to a fur trade rendezvous on the Green River near the future town of Big Piney, Wyoming.

The Platte River and North Platte River valley, however became an easy roadway for wagons, with its nearly flat plain sloping easily up and heading almost due west.

Captain Benjamin Bonneville on his expedition of 1832 to 1834 explored much of the Oregon trail and brought wagons up the Platte, North Platte, Sweetwater route across South Pass to the Green River in Wyoming.

One of the better known ferries was the Mormon Ferry across the North Platte near the future site of Fort Caspar in Wyoming which operated between 1848 and 1852 and the Green River ferry near Fort Bridger which operated from 1847 to 1856.

Multiple ferries were established on the Missouri River, Kansas River, Little Blue River, Elkhorn River, Loup River, Platte River, South Platte River, North Platte River, Laramie River, Green River, Bear River, two crossings of the Snake River, John Day River, Deschutes River, Columbia River, as well as many other smaller streams.

Because it was more a network of trails more than a single trail there were numerous variations with other trails eventually established on both sides of the Platte, North Platte, Snake, and Columbia rivers.

Map showing the Platte River watershed, including the North Platte and South Platte tributaries

While unusable for transportation, the Platte River and North Platte River valleys provided an easily passable wagon corridor going almost due west with access to water, grass, buffalo, and buffalo chips for fuel.

The Platte River in the future state of Nebraska and the North Platte River in Wyoming typically had many channels and islands.

The South Platte River ( Arapaho: Niinéniiniicíihéhe ' ) is one of the two principal tributaries of the Platte River and is itself a major river of the American Midwest and the American Southwest / Mountain West, located in the U. S. states of Colorado and Nebraska.

Popular legend states the founder of Ville Platte was Marcellin Garand, an adjutant major in the Army of the French Empire, during the time of Napoleon.

Atop the Platte Mound and the M viewers can see three states: Wisconsin, Iowa, and Illinois.

The Laramie River is a tributary of the North Platte River, approximately long, in the U. S. states of Colorado and Wyoming.

* Joliet Township, Platte County, Nebraska

After ferrying across the Missouri River and establishing wagon trains near what became Omaha, Nebraska, the Mormons followed the northern bank of the Platte River in Nebraska to Fort Laramie in present day Wyoming.

After the Vermillion River the trail angles north west to Nebraska paralleling the Little Blue River until reaching the south side of the Platte River.

Until about 1870 travelers encountered hundreds of thousands of bison migrating through Nebraska on both sides of the Platte River, and most travelers killed several for fresh meat and to build up their supplies of dried jerky for the rest of the journey.

After crossing the South Platte River the Oregon Trail follows the North Platte River out of Nebraska into Wyoming.

It joins the North Platte River in western Nebraska to form the Platte, which then flows across Nebraska to the Missouri.

In Nebraska, it passes south of Ogallala and joins the North Platte River near the city of North Platte.

Those traveling south of the Platte crossed the South Platte River with its muddy and treacherous crossings using one of about three ferries ( in dry years it could sometimes be forded without a ferry ) before continuing up the North Platte River valley to Fort Laramie in present-day Wyoming.

Those traveling south of the Platte crossed the South Platte fork at one of about three ferries ( in dry years it could be forded without a ferry ) before continuing up the North Platte River valley into present-day Wyoming heading to Fort Laramie.

The Comanche emerged as a distinct group shortly before 1700, when they broke off from the Shoshone people living along the upper Platte River in Wyoming.

This territory included what is now Colorado, east of the Front Range of the Rockies and north of the Arkansas River ; Wyoming and Nebraska, south of the North Platte River ; and extreme western Kansas.

In April 1856, an incident at the Platte River Bridge ( near present-day Casper, Wyoming ), resulted in the wounding of a Cheyenne warrior.

Nonetheless, this famous expedition had mapped both the eastern and western river valleys ( Platte and Snake Rivers ) that bookend the route of the Oregon Trail ( and other emigrant trails ) across the continental dividethey just had not located the South Pass or some of the interconnecting valleys later used in the high country.

In the Nebraska license plate system, Platte County is represented by the prefix 10 ( it had the tenth-largest number of vehicles registered in the county when the license plate system was established in 1922 ).

the Otoe had moved from central Iowa into the lower Platte Valley in the early 18th century ;

The pioneers leaving from near Omaha ( established 1854 ) or Council Bluffs, Iowa ( established 1846 ) used the Mormon Trail north of the Platte River and had to ferry across the Elkhorn.

Occupied by various Indian tribes for part of each year, the Platte River territory had been claimed by both Spanish and French explorers trying to rule the Great Plains.

By 1714 ( the same year the French explorers " discovered " the Platte ), he and a small exploration group from the south had reportedly already reached the Platte three times.

By about 1832, the fur traders had improved the trail along the Platte, North Platte, and Sweetwater rivers to a rough wagon trail from the Missouri River to the Green River in Wyoming, where most of the Rocky Mountain Rendezvous were held.

The Platte route had access to water, grass, buffalo and buffalo ' chips ,' which the Indians and emigrants used as fuel for fires.

Long Native American use had created trails on both sides of the muddy, about wide and shallow ( to ) Platte River.

In the early 19th century, the Iowa had reached the banks of the Platte River, where in 1804 Lewis and Clark visited their settlements.

In the spring of 1865 raids continued along the Oregon trail in Nebraska and the Sioux, the Northern Cheyenne, the Northern Arapaho together with the warriors who had come north after the Sand Creek massacre raided the Oregon Trail along the North Platte River, and in July 1865 attacked the troops stationed at the bridge across the North Platte at the present site of Casper, Wyoming, the Battle of the Platte Bridge Station.

Other members of the peace commission were Lieutenant General William T. Sherman, commander of the Military Division of the Missouri ; Major General William S. Harney ( retired ), who had taken part in earlier conflicts with the Cheyenne and Sioux along the Platte River ; Brigadier General Alfred H. Terry, commander of the Military Department of Dakota ; Senator John B. Henderson of Missouri, Chairman of the Senate Indian Appropriations Committee, who had introduced the bill that created the peace commission ; Colonel Samuel F. Tappan, formerly of the First Colorado Volunteer Cavalry and a peace advocate who had led the U. S. Army's investigation of the Sand Creek massacre ; Major General John B. Sanborn, formerly commander of the Upper Arkansas District, who had previously helped to negotiate the Little Arkansas Treaty of 1865.

The event became a national news sensation but was soon overshadowed by the Platte Canyon High School Shooting which had occurred only hours later.