What is now the State of Platte was originally part of the Upper Louisiana Territory, which was part of the Louisiana Purchase of 1803. It was later broken off from the state of Louisiana following the War of 1812. From 1815 until 1840, the territory was administered from Fort Jefferson, just west of the confluence of the Platte and Missouri Rivers. Despite some limited presence of Euro-American settlers along these two rivers, much of the territory remained the domain of several native nations, including the Pawnee, Omaha, and Otoe. While the farmland in the region was promising, the rivers in the area were a far cry from the easily navigable Mississippi, so the region was slow to bring in people from back East - at least, those that wanted to stay. Fort Calhoun and the few other military forts and civilian outposts, such as Fort Adams, further along the Platte, and what is now the city of Confluence, where the Niobrara and Missouri Rivers meet, largely served the scores of people who were starting to trek west to the Oregon Country. 

By 1840, during the Yates Administration, there were enough people living in the land between the Kansas and Missouri/Niobrara Rivers that Congress felt it appropriate to separate this section of land off from the rest of the remaining Upper Louisiana Territory (which had had Iowa, Arkansas, and Kanasaw Territories broken off in the 1820s). The Platte Territory was officially established on January 15th, 1840. Fort Jefferson remained the territorial capital (with Upper Louisiana now being administered from Fort of the West - now Metropolis - in what is now Metropotamia). Despite being one step closer to statehood, settlement remained closely tied to the Missouri, Platte, and Kansas Rivers, and grew slowly. It wouldn’t be until the 1850s that Platte would reach the 60,000-person population threshold required for statehood. 

Throughout this period, Platte functioned primarily as a corridor rather than a destination. Emigrant trains bound for Oregon and the western mountain territories crossed the plains in growing numbers, following routes that paralleled the Platte River. To serve this traffic, a loose network of ferries, supply depots, inns, and repair yards developed along major crossings. Many of these places were never intended to become permanent towns, yet some endured as settlers chose to remain, drawn by inexpensive land and the steady demand created by westward migration. By the end of the decade, agriculture had taken hold in pockets across the territory, even as vast areas remained sparsely populated.

The all-important 60,000 people milestone was achieved in mid 1853, and very quickly, the territorial legislature began to clamor for statehood, and worked with their counterparts in St. Augustine, Florida, to petition Congress for statehood - abiding by the Grantham Act, which required that statehoods be paired - one slave, and one free. Florida would receive its statehood on February 27th, 1854, with Platte joining just days later on March 1st, becoming the 30th state in the Union. At the state capital (renamed Fort Calhoun in 1849), the Democratic Party held sway, advocating measures to help grow the state and encourage the nation's continued westward expansion. Slavery was not well-liked in the state, but the consensus among most Platteans was that the “abhorrent institution” should be handled by the states - it was not a federal matter. 

In less than two years, the nation found itself on the brink of crisis. President Robert Lee was shot by a radical abolitionist in November of 1855, and died in early 1856, thrusting his vice president, James Hawthorne, into the presidency. Hawthorne came down hard on those he perceived to have been behind the assassinations, and in general on anyone who was publicly opposed to slavery, and by 1857, New England had seceded from the Union. Hawthorne’s government was becoming increasingly tyrannical in its efforts to stamp out the rebellion. By 1858, Democratic-dominated northern states had begun to secede as well. Platte initially resisted this sentiment, but changed course when Hawthorne overthrew the government of Kentucky, which seemed likely to be sympathetic to the northern, anti-slavery cause. On September 19th, 1858, the Platte Legislature voted nearly unanimously to join the Free States, no longer recognizing James Hawthorne’s government as the legitimate government of the United States. 

There would be little actual fighting in Platte, or anywhere in the West, but nearly 6,000 men from the state would join the Free State Army in its pursuit of reclaiming the republic from the Slavers. The only real “battle” of note was at Fort Adams, where the local army commander, a Southerner, initially refused to surrender the fort. The state militia surrounded the outpost, and on October 20th, the local Union forces surrendered. 

After the war ended in 1860, Platte’s governor, Harrison Bently, was the first northern politician of note to call on Acting President Brandt to include Southerners in the new constitutional convention. Platte’s representatives were instrumental in crafting the Western Homestead Acts after the war, and the state acted as a testing ground for the new programs. In addition to a flood of individual homestead claims springing up in the state over the course of the 1860s and 1870s, several major communal homesteads were established, including Liberty, southwest of Fort Calhoun, which became one of the most successful Freedmen communities west of the Mississippi, and Sentinel, a veteran’s commune, which became a major stop on the Fifth National Road and Rail Line, which became the transcontinental connection out to Oregon.