Augustus Pelletier never forgot the Shining Sea. He returned with the Lewis and Clark expedition which arrived in St. Louis on September 23, 1806. He continued to assist Meriwether Lewis with the organization of his notes, journals, and various specimens even after Captain Lewis had been appointed governor of the Louisiana territory. Lewis however fell into a deep depression and committed suicide on October 11, 1809. At that time Captain William Clark turned his and Lewis’s journals over to Nicholas Biddle, a Philadelphia lawyer, to edit. He recommended that Biddle hire Augustus Pelletier, who was the person most familiar with Lewis’s notes and specimens. Augustus worked for a time with Biddle but then became frustrated with the slow pace of the work. He longed to see the Shining Sea again. At the age of twenty he hired himself out as a guide for the Missouri Fur Trading company. He soon became known as a good fur trader and at the mouth of the Columbia river opened a trading station that served American ships purchasing furs from the China trade which was just beginning.

Augustus was very successful yet there was great unrest among the Indians. On a trip back east to explore the possibilities of opening an office in St. Louis for his fur trading he saw Sacajawea. She had remained for a time in Saint Louis, with her son Jean Baptiste, at the home of Captain William Clark, who had married his sweetheart, Judith. She then joined Charbonneau on the upper Missouri where he spent the rest of his life interpreting for government officials. They did however leave their son Jean Baptiste behind with the Clark family to be educated. In 1812 Sacajawea gave birth to a second child, a daughter Lisette, at Fort Mandan but later that winter Sacajawea fell ill and died.

When Augustus learned of Sacajawea’s death he was deeply saddened. Captain Clark had promised to educate Sacajawea’s children and it was Augustus who helped arrange for the tiny child Lisette to be returned to St. Louis. He visited the children regularly over the years in the Clark home and on one occasion met a music teacher engaged for Lisette and fell in love with her. Her name was Emily Calderwood. They married and for their honeymoon they traveled up the Missouri once again. He took Emily to a new falls that he discovered on one of his fur trading trips. It was not far from the ones he had named for his mother. These falls however he named Emily for the sound of its water was as musical as his bride’s voice.