village by De Smet, showing earthlodges and other traditional house forms. One of De Smet's longest explorations began in August 1845 in the region west of the
Rockies that was jointly occupied by the Americans, who called it
Oregon Country, and the British, who identified it as
Columbia District. De Smet started from
Lake Pend Oreille in present-day north
Idaho and crossed into the
Kootenay River Valley. He followed the Kootenay valley north, eventually crossing over to
Columbia Lake, the source of the
Columbia River at
Canal Flats. He followed the upper Columbia valley north to and past
Lake Windermere. At
Radium Hot Springs, he turned east and went over
Sinclair Pass into the Kootenay River Valley. He recrossed the Kootenay and continued along the reverse of the route pioneered by the
Sinclair expedition. He followed the
Cross River upstream to its headwaters at Whiteman's Pass. The Cross River was named for the large wooden cross that De Smet erected at the top of the pass, where it could be seen from miles away. On the other side of the
Great Divide was the British territory of
Rupert's Land. From the crest of the pass, streams lead to Spray Lakes above present-day
Canmore, Alberta, and the
Spray River, which joins the
Bow River near modern-day
Banff, Alberta. Once in the Bow Valley, De Smet headed upstream and in a north-westerly direction to its source
Bow Lake. He traveled further north until he came to the
North Saskatchewan River, which he followed downstream and east. It was October, and a long cold winter was looming, when he reached
Rocky Mountain House. He had fulfilled one of his main goals; to meet with the
Cree,
Chippewa, and
Blackfoot of the area. At the end of the month, De Smet traveled further to the east to search for other Natives. Fortunate to find his way back to Rocky Mountain House, Natives guided him to
Fort Edmonton, where he spent the winter of 1845–1846. During these years, he established St. Mary's Mission in present-day
Stevensville, Montana, among the Flathead and Kootenay Indian tribes. He also established the mission that became the Sacred Heart Mission to the Coeur d'Alene in present-day
Cataldo, Idaho. In the spring of 1846, De Smet began his return westward, following the established
York Factory Express trade route to the Columbia District. He went west to
Jasper House, and with considerable hardships completed the trek. He then crossed the Great Divide by
Athabaska Pass, traveling to the
Canoe River, the northernmost tributary of the Columbia River, and eventually on to
Fort Vancouver, some thousand miles (1600 km) to the southwest. He eventually arrived at his mission at Sainte-Marie on the
Bitterroot River. His book
Oregon Missions and Travels over the Rocky Mountains in 1845 to 1846 was published in 1847. ==Later years and death==