The Corps of Discovery left their campsite where Fort Union is now located and followed the Missouri River into what is now Montana. Besides the two captains, there were three sergeants, 23 enlisted men, Clark’s black slave, York, two interpreters, Drouillard and Charbonneau, Charbonneau’s wife, Sacajawea and her 2-month-old son, Baptiste (nicknamed Pomp) and Seaman, Lewis’s Newfoundland dog. They came in six canoes and two round boats called pirogues. The campsite that night was one mile down from the community of Nobly in Richland County and the site of Snowden Bridge.

They covered 24 miles. Lewis: “the beaver have cut great quantities of timber; saw a tree nearly 3 feet in diameter that had been felled by them.” Camped on the south side of the river across from Otis Creek.

Lewis saw and shot his first grizzly bear which pursued him 70 or 80 yards before the second shot killed him. He wrote: “…this animal appeared to me to differ from the black bear; it is a much more furious and formidable animal, and will frequently pursue the hunter when wounded.” Camped just above Big Muddy Creek in Roosevelt County.

Clark, Charbonneau and Sacajawea walked along the shore most of the day. Lewis shot a bull elk which measured 5 feet three inches from hoof to top of the shoulder. Camped on the north side near the present Brockton.

Lewis wrote: “…the wind being favorable we used our sales which carried us on a good pace until about 12 Ock. when the wind became so high that the small canoes were unable to proceed.” Spent the rest of the day and night on the south side in the vicinity of the later Elkhorn Point.

A violent wind blew all night “...at daylight it was attended with snow... being about one inch deep, it formed a singular contract with the vegitation which was considerably advanced...some flowerss had put forth in the plains...” Camp was near the crossing of Montana Highway 251 in Richland County.

Went several miles up Porcupine River and named a “bold running stream” 2000 Mile Creek, (Redwater now) because that is how far they figured they had come from St. Louis. They camped three or four miles above the present town of Poplar. This site is not certain because of shifts in the river.

“We were detained this morning until about 9 Ock. in order to repare the rudder irons... which were broken last evening in landing;…passed several old Indian hunting camps…” Traveled 18 miles and camped on the north shore (Roosevelt County between Poplar and Wolf Point).

“saw the carcasses of many Buffaloe lying dead along the shore partially devoured by the wolves and bear.” Clark found a den of young wolves, possibly coyotes. “my dog caught a goat (antelope) which he overtook by superior fleetness, the goat it must be understood was with young and extremely poor.” They camped southeast of the present town of Wolf Point. Due to shifts in the river, the campsite is now on the opposite side and a mile or two from the river.

Lewis: “a fine morning …passed two Creeks and a River today on the Lard…the country on both sides butifull…” Camped on a point on the south side of the river (now McCone County), a few miles southwest of the present town of Oswego.

“the country we passed today on the North side of the river is one of the most beautiful plains we have yet seen, it rises gradually…then becoming level as a bowling green…as far as the eye can reach” Camped on the south bank, a few miles southwest of the present town of Frazer.

Again they found shelter in abandoned Indian lodges and stayed two days to dry out. “Had showers of rain repeatedly all day...at 2 p.m. I was obliged to land to let the Buffalow Cross over...this gangue of Buffalow was entirely across and as thick as they could swim...I was obliged to lay to for an hour.”

After passing by the future town of Sidney, Clark and his detachment paddled out of Montana for good about 3 miles south of Fairview. They spent the night east of Fairview on the Yellowstone River in North Dakota at the mouth of Charbonneau Creek.

Lewis, in a hurry to meet Clark, did not stop for lunch and set out the next morning, August 4, at 4 a.m. That day they passed the mouths of the Big Dry (which had water this time) and the Milk River.

The group waited, in vain, until noon for Colter and Collins, who had gone hunting, to catch up with them. That night, a violent storm arose and lasted through the next day, August 6, hampering their progress.

“…at 8 a.m. we passed the entrance of Marthy’s river (Big Muddy Creek) which has changed it’s entrance since we passed it last year…” They arrived at the mouth of the Yellowstone at 4 p.m., and found a note that Clark had left August 4, saying: “Musquetors excessively troublesom So much So that the men complained that they could not work at their Skins for those troublesom insects. And I find it entirely impossible to hunt in the bottoms…The torments of those Missquetors…induce me to deturmine to proceed on to a more eliagliable Spot…”

Both men (Clark on the 2nd and Lewis on the 7th) left Montana worried about each other and bothered by mosquitoes. On August 12, Colter and Collins caught up with Lewis along the Missouri River at a point which is now under Garrison Reservoir. The same day he wrote: “…at 1 p.m. I overtook Capt. Clark and party and had the pleasure of finding them all well.”