Mormon History, Feb 27, 1846

William Clayton Leaves Nauvoo, following the first Mormon emigrants who had crossed the Mississippi River on February 4.

[source: Smith, George D., An Intimate Chronicle; The Journals of William Clayton, p.lxiii, A William Clayton Chronology, http://amzn.to/william-clayton]
[Smith, George D., An Intimate Chronicle; The Journals of William Clayton, p.lxiii, A William Clayton Chronology, http://amzn.to/william-clayton]