The roving fur-traders were quick to pene trate the regions pioneered by Lewis and Clark and Pike. During the years 1806-09 they ex tended their excursions well into the Rocky Mountains from the east. In Canada the North western Company, ever active, pushed its out posts westward; and in 1808 one of its agents, Simon Fraser, reached the Pacific at the mouth of the Fraser River.
In 1810 John Jacob Astor, a New York fur trader, organized a company for the purpose of exploiting the trade on the Pacific slope. A vessel was dispatched to the mouth of the Columbia River to establish a post and an ex pedition sent overland to follow the Lewis and Clark route. This was the second party to cross the United States to the Pacific. Numbering three boats and 60 men under the leadership of one of the partners, Wilson Price Hunt, it left Saint Louis in the late summer of 1810 and pushed its way up the Missouri about 450 miles. Here the party wintered and in the spring continued by boat to the big bend of the Missouri; then with horses purchased from the Sioux proceeded overland in a southwesterly direction; crossed the Rockies near the head of the Big Horn River and followed the Snake River Valley to the Columbia. With only a fraction of his large party and after the most terrible suffering, Hunt reached the mouth of the Columbia in February 1812, and found As toria, the post established by the party sent by sea. The American company was only just in time; the previous year David Thompson of the Northwestern Company had portaged across the Rockies from the Saskatchewan to the head waters of the Columbia and followed it to the Pacific, where, much to his disgust, he found the Americans already in possession.
In 1812 David Stuart, with a small party, started eastward from Astoria to make the diffi cult and hazardous journey to Saint Louis. He chose a route to the head waters of the Snake, across the divide to the Green River, a tributary of the Colorado, and across a second divide to the Platte, which he followed to its junction with the Missouri and continued down stream to Saint Louis, arriving in April 1813, after a journey full of peril and hardship.
In 1814 Astoria passed into the hands of the Northwestern Company, which extended its trade over the entire Columbia River basin and established posts at various points. The eastern
slope of the Rockies was occupied by American traders, with headquarters at Saint Louis and posts on the upper Missouri in the Green River Valley, The government began to realize the im portance of exploration. In the hope of discov ering the sources of the Red River, a large ex pedition under Maj. Stephen H. Long left Pitts burgh on a small steamer in April 1819, wintered on the lower Missouri and during the following year made explorations and surveys in the country now included in Arkansas and Mis souri. Long was sent again in 1828 to explore the head waters of the Mississippi, which he approached through the wilderness from the Miami River to Lake Michigan, thence to the junction of the Wisconsin and Mississippi and on to the Minnesota ; a difficult route, but lying in a region which had been explored by French pioneers more than a century before.
Still the source of the Mississippi had not been discovered. The head water region, pre viously visited by Pike and long the stamping ground of the fur-trader, had been again ex plored in 1820 by Gen. Lewis Cass, governor of Michigan, in company with Hen7 R. School craf t. It was not until 1832 that the source was finally discovered in Lake Itasca by Schoolcraft and Lieut. J. Allen.
Capt. B. L. E. Bonneville, an officer of the United States army, in 1832 organized a party of trappers and hunters for the ostensible purpose of taking part in the fur-trade, but more to gratify his own ambition to explore the Far West. He left Fort Osage on the Missouri with 110 men, transporting his supplies by means of wagons, instead of using pack-animals, as all previous parties had done. Following Stuart's route of 20 years before along the valley of the Platte River, he crossed the mountains with his wagon train and established a post at the head of the Green River. From this point as rendezvous his party scattered out in various directions, he himself exploring the Big Horn and Wind River mountains and extending one journey to the English trading-post on the Columbia. A party sent out by him visited Salt Lake and con tinued through to the Spanish settlement of Monterey on the Pacific.