Preston's Map of Oregon and Washington

You can read Preston's Oregon and Washington as a settler guide rather than as decoration. Its counties and survey lines make sense only against the wagon road from Missouri to Oregon City and the farm country beyond the Rockies.

What did the Oregon Trail connect on paper?

You start in the east on the Missouri River and you finish in the west in the valleys of Oregon Territory. The page gives the length as 2,170 miles and describes an east-to-west route for large-wheeled wagons. The eastern part crossed what is now Kansas, Nebraska, and Wyoming, while the western half crossed what is now Idaho and Oregon. For a map reader in the East, that division helped you judge scale. You were not looking at a single state. You were tracing a line across present-day states from Independence, Missouri to Oregon City, Oregon. Later feeder routes also left from Weston, Fort Leavenworth, Atchison, St. Joseph, and Omaha, and from Iowa, Missouri, or Nebraska Territory, with routes that converged along the lower Platte River Valley near Fort Kearny. If you follow landmark maps explained plate by plate, you can see why publishers kept the start and the finish so prominent.

Why does the valley route matter for counties?

You need grass and water for animals, so you need river valleys. The basic route follows river valleys because travel depended on feed and stream crossings. From the Platte and North Platte to the Sweetwater, Bear, Snake, and Columbia, water set the line of march. A county square on a printed map can look empty, but on the ground it meant access to a creek, a ford, or a campsite. The trail was laid by fur traders and trappers from about 1811 to 1840 and was at first passable only on foot or horseback. By 1836, when the first migrant wagon train was organized in Independence, a wagon trail had been cleared to Fort Hall in Idaho. Later clearing reached the Willamette Valley, after which the road can be called complete. Bridges, cutoffs, ferries, and roads then made the trip faster and safer.

Forts as fixed points for a new arrival

You can use forts to orient yourself on an early state map. Fort Kearny, about 200 miles from the Missouri River, was the first Army-maintained opportunity to buy emergency supplies, do repairs, get medical aid, or mail a letter. Farther west, Fort Laramie at the confluence of the Laramie and North Platte rivers was a former fur trading post bought by the Army in 1848 to protect travelers. Fort Hall on the Snake River began as a fur trading post set up in 1832 by Nathaniel Jarvis Wyeth and sold in 1837 to the Hudson's Bay Company, and Fort Boise and Fort Nez Perce stood near the western end of the route. Fort Vancouver on the Columbia served many travelers as a place to get supplies, aid, and help before they started homesteads. On a map of Oregon and Washington, these names let you measure how far settlement had moved past the trading period.

How did cutoffs and branches change the reading of distance?

You should not read the trail as one thin line. It was a network with variations on both sides of the Platte, North Platte, Snake, and Columbia rivers, and at times 20 to 50 wagons might travel abreast where ground allowed. The Sublette-Greenwood Cutoff, established in 1844, cut about 70 miles off the main route but crossed about 45 miles of waterless and dusty ground before the Green River. The Lander Road, built by government contractors in 1858 and 1859, was about 80 miles shorter than the main trail through Fort Bridger but crossed three mountain ranges and proved steep and rough. Near Fort Hall the California Trail left the Snake and followed the Raft River toward the City of Rocks and the Humboldt River, while travelers bound for the large-wheeled wagon route kept northwest toward the Columbia. Hudspeth's Cutoff, Goodale's Cutoff, and the South Alternate show the same lesson for map users. A shorter line did not always mean an easier day.

Surveys, rivers, and the limits of wagon travel

You can learn much from how rivers are drawn. The Platte and North Platte often ran in many channels and islands, too shallow, crooked, muddy, and unpredictable for travel even by canoe, yet the valleys gave an almost level wagon corridor heading west with water, grass, and fuel. South Pass over the Continental Divide gave wagons a practical crossing with little improvement, and Stuart's journals left a careful account of much of the route. On the Sweetwater the trail had to cross the stream up to nine times before the pass. The Green River, deep, wide, swift, and often high in July and August, needed three to five ferries in peak periods. At Three Island Crossing near present-day Glenns Ferry, travelers used river divisions formed by three islands to cross the Snake, sometimes by ferry, sometimes by driving or floating wagons and swimming stock. Ferries raised the cash cost by about 30 dollars per wagon but cut the average trip from about 160 to 170 days in 1843, to 120 to 140 days in 1860.

Who was walking beside you on the road west?

You were not alone on the eastern half. That section was also used by California Trail travelers from 1843, Mormon Trail travelers from 1847, and later Montana and Bozeman traffic, before each turned toward a separate destination. About 400,000 settlers, farmers, miners, ranchers, and business owners and their families used the Oregon Trail and its offshoots to reach Oregon and nearby country, with especially heavy traffic from 1846 to 1869. The Mormon movement added farms, ferries, and trail work, including the Salt Lake Cutoff north of the Great Salt Lake that rejoined the main trails near the City of Rocks. After gold was found in January 1848 in the Sierra Nevada portion of the American River, many Oregon men went to California and traffic rose sharply on both the Oregon and California roads. Cholera struck hard from 1849 to 1855 along shared camping places on freshwater streams, and most victims were buried in unmarked graves in Kansas, Nebraska, and Wyoming. Livestock droves also crowded the corridor, and in some years animals may have matched or exceeded the number of emigrants.

What can you check next on the plate itself?

You can test a county map against the passes and fords named above. Look for Independence Rock on the Sweetwater, South Pass, Fort Bridger, Bear River Valley, Fort Hall, Three Island Crossing, Old Fort Boise, Grande Ronde Valley, the Blue Mountains, the Umatilla, John Day, and Deschutes rivers, The Dalles, the Columbia River Gorge, the portage around the Cascade Rapids, and the Willamette Valley. In 1843 wagons were stopped at The Dalles for lack of a road around Mount Hood and had to be disassembled and floated down the Columbia while animals were herded over the rough Lolo trail. The Barlow Road, completed in 1846 around Mount Hood, charged 5 dollars per wagon and 10 cents per head of stock and gave a rough but passable wagon trail to the valley. The Santiam Wagon Road and the Applegate Trail provided other entries. For classroom work, the guide to using historic maps in the classroom suggests that you ask students to trace one river at a time and mark each crossing. Use of the trail fell after the first transcontinental railroad was completed in 1869, when rail made the trip faster, cheaper, and safer, and parts of the course are now followed by Interstate 80 and Interstate 84. Lay a straightedge from Fort Hall to The Dalles and note where the printed county lines cut across the river bends you just traced.