The Lewis and Clark Expedition (1804–1806), commissioned by Thomas Jefferson following the Louisiana Purchase and lead by Meriwether Lewis and William Clark, was the first American overland expedition to the Pacific coast and back. In 1804 the expedition wintered in North Dakota where they employed a fur trapper named Toussaint Charbonneau as a translator; he was accompanied by his young Shoshone wife, Sacajawea, who also translated for the expedition among the Shoshone and Nez Perce. After the expedition, the couple settled in St. Louis, Missouri. After they died – sometime before 1813 – Clark adopted their children; there is no evidence any relationship between Clark and Sacajawea.
The Far Horizons is a heavily-fictionalised movie adaptation of a novel, where Sacajawea (Donna Reed) falls in love with Clark, who is – of course – going to marry a white woman.
Wally Westmore was makeup supervisor. I understand that Charles Gemora (uncredited) was responsible for Donna Reed’s makeup.