The following article was written by my good friend, Bill Dollarhide, and is taken from his book, Montana Censuses & Substitute Name Lists, 1860-2014.
Prologue: The highlighted events of this historical timeline for Montana are focused on the early settlements and jurisdictional changes that evolved. The goal here is to give genealogists a sense of the jurisdictions in place at the time an ancestor lived there. For example, this timeline shows that a search for early Montana records may send a researcher to Oregon Territory, Washington Territory, Idaho Territory, Dakota Territory, Montana Territory, and finally, the state of Montana. And, for an understanding of the county jurisdictions, the map of Montana Territory at the time of the 1870 census shows both the first 11 counties of the territory, and the 56 modern counties of the state on the same map.
1803. Lewis and Clark Expedition. Captains William Clark and Meriwether Lewis led the Corps of Discovery, the first transcontinental expedition of the lands west of the Missouri River. Their trek to the Pacific was mostly via river routes, beginning at St. Louis on the Mississippi, up the Missouri River to its source in Montana, then by foot across the Mountains, picking up Idaho’s Clear River, to the Snake River of Idaho and Washington, and finally, the Columbia River all the way to its mouth at present Astoria, Oregon.
1807. British Canadian fur trader and mapmaker David Thompson, with the Montreal-based North West Fur Company, began looking for routes from the Rocky Mountains to the Pacific Ocean. He led a crew of French-Canadian fur trappers, established fur trading opportunities with any Indian tribes encountered, and charted detailed maps of the Columbia River. From 1807 to 1809, Thompson established the first trading post in present Montana at Kootenai Falls near Libby; the first in present Idaho, Kullyspell House, on Pend Oreille Lake; and the first trading post in present Washington, now Bonner’s Ferry, on the Columbia River.
1807. Fort Raymond. Fur trader Manuel Lisa established Fort Raymond, a fur trading post in present day Montana, at the mouth of the Bighorn River on the Yellowstone River.
1807. John Colter, recent member of the Lewis and Clark expedition, now a mountain man, fur trapper, and explorer, was the first to describe a place where “hot water shoots straight into the air, the earth bubbles as if it were boiling, and almost extinct geysers thunder as if possessed by angry spirits.” He referred to the area in his written report as Colter’s Hell. Most easterners believed he was lying or exaggerating – it was hard to believe such a place could really exist. Colter’s Hell is now called Yellowstone National Park.
1818. Anglo-American Convention. Britain and the U.S. agreed to the 49th parallel as the international boundary from the Lake of the Woods (now Minnesota) to the Continental Divide (in present Montana).
1818. Oregon Country. Also in the 1818 treaty, The United States and Great Britain agreed to a joint occupation of the Oregon Country/Columbia District. Both parties accepted the area as extending from the Continental Divide to the Pacific Ocean, and from about Latitude 54° in present British Columbia, to the Boundary Mountains (now Siskiyou Mountains) at about Latitude 42° ). In 1827 a provision was added to the treaty that allowed either party to invoke a conclusion of ownership, by giving 12 months notice to the other. Notice was not given until 1845, when President James K. Polk sought resolution, leading to a new treaty in 1846.
1828. Fort Union. At the mouth of the Yellowstone River on the Missouri River (near the present Montana-North Dakota line), an earlier Fort Henry was taken over by the American Fur Company in 1828 and renamed Fort Union. It became the center for John Jacob Astor’s fur trading empire in the northern Plains.
1832. The first steamboat into Montana was the Yellowstone, which began annual trips from St. Louis up the Missouri River to Fort Union. Similar to the annual rendezvous system used in Wyoming and Idaho, the early fur traders of Montana converged on Fort Union every Fall to trade their furs for supplies, weapons, and cash.
1839. Fr. Pierre-Jean DeSmet arrived among the Flatheads in the Bitterroot Valley of present Montana. He and his staff would set up a number of Jesuit missions in the present states of Montana, Washington and Idaho.
1841. St. Mary’s Mission, the first permanent settlement by Europeans in the Montana area was established by Jesuit missionaries led by Fr. DeSmet.
1847. Fort Benton was established on the Missouri River as a military and trading post. It soon became the “Head of Navigation” to the west, and the world’s furthest inland port. Steamboats brought gold seekers, fur traders, settlers and supplies, making Fort Benton the “Birthplace of Montana.” Of all the forts on the Missouri and Yellowstone rivers, Fort Benton is the only one that continues as a town today. It is located in north central Montana, about 30 miles northeast of Great Falls.
1848. Mexican Annexation. On February 2nd, the Treaty of Hidalgo Guadalupe was signed, ending the war with Mexico. As part of the treaty, the Mexican provinces of California and Santa Fe de Nuevo Mexico were annexed to the U.S., which included the present states of California, Nevada, Arizona, New Mexico, Utah, and western Colorado.
1848. August 14th, Oregon Territory was created by Congress. It encompassed the area between the 42nd and 49th parallels, from the Pacific to the Continental Divide. The first capital was Oregon City.
1850. June. Federal Census taken in Oregon Territory, which included the area of present Oregon, Washington, and Idaho; and Montana and Wyoming areas west of the Continental Divide. The population was revealed as 12,093 people. No population was recorded in the present Idaho, Montana, or Wyoming areas.
1853. Washington Territory was created by Congress. It encompassed the present area of Washington, but extended east to the Rocky Mountains, incorporating areas that today are in northern Idaho and western Montana. As a result, the original Oregon Territory was split in half. Oregon Territory now had lands on the same line as its present northern border stretching to the Continental Divide, and included the southern half of present Idaho, and a portion of present western Montana and Wyoming.
1859. Oregon joined the Union as the 33rd state, a Free State with the same boundaries as present. The population of the new state was about 45,000 people. The eastern remnants of Oregon Territory, 1853-1859, were added to Washington Territory.
1860. June. Federal Census. Washington Territory. The population was at 11,594. The area included present Washington and Idaho; and areas west of the Continental Divide in present Montana and Wyoming. The only recorded population outside of the present Washington bounds was for the residents of the Bitterroot Valley and Ponderay Mountain areas of present Montana; and a few farmers in Idaho’s Bear Lake area taken as part of Cache County, Utah Territory.
1860. June. Federal Census. Unorganized Dakota. Present Montana east of the Continental Divide was part of Nebraska Territory, but for convenience the trading posts of Fort Union on the Missouri River and Fort Alexander on the Yellowstone River were enumerated in 1860 as part of Unorganized Dakota. Fort Benton and a couple of other outposts in Montana were missed.
1861. Dakota Territory was created, with boundaries that included all of Montana and Wyoming east of the Continental Divide; and the areas of present North Dakota and South Dakota.
The first Idaho Territory, March 1863
1863. Idaho Territory was created, with boundaries that included all of present Idaho, Montana, and Wyoming areas. This large area was short-lived, however, as Montana Territory was taken from the Idaho area a year later.
Montana Territory, created in 1864
1864. Montana Territory was formed, taken from the obese Idaho Territory. From its beginning, Montana Territory had the same boundaries as the present state. The original area proposed for Montana Territory included what is now Idaho’s northern panhandle, but Congress decided to keep that area as part of Idaho to offset the Mormon population in southern Idaho. The first territorial capital of Montana was established at Bannack, followed by Virginia City in 1865, and finally, Helena in 1875.
1870. June. Federal Census. Montana Territory. The population was at 20,595. The first eleven counties of Montana Territory, 1864-1867, are shown in black on the 1870 map above. The 56 modern counties of the state of Montana today are shown in white. An excellent List of Counties in Montana is a Wikipedia site, with good details about Montana’s 56 counties, dates established, origin, etymology, population, and size.
1880. June. Federal Census. Montana Territory. The population was at 39,159.
1889. Nov. 8th. Montana became the 41st state, with the state capital at Helena.
Montana Censuses & Substitutes, 1860-2014 [Printed Book], 2017, softbound, 81 pages, Item FR0261.
Montana Censuses & Substitutes, 1860-2014 [PDF eBook], 2017, 81 pages, Item FR0262.
Online Montana Censuses & Substitutes: A Genealogists’ Insta-Guide™ , 4 -page, laminated, 3-hole punched, Item FR0331.
Online Montana Censuses & Substitutes: A Genealogists’ Insta-Guide™, (PDF version), 4-page, Item FR0332.