Millen Atwood was a member of the 10th Quorum of Seventies. He traveled in the 1847 Brigham Young Company as part of the 3rd Company of Ten, headed by Phineas H. Young. His obituary indicates he traveled to the Valley initially in 1847 in the vanguard company, then returned to Nauvoo to obtain supplies. He returned again to Salt Lake the following year, again in Brigham Young's company.
He sailed back to America in 1856 on the ship Thornton, and he again crossed the plains in 1856 while returning from a mission in Europe.