Johnston, Daniel W.
Daniel W. Johnston was the son of Abraham Lincoln's stepbrother, John D. Johnston, and was therefore Lincoln's nephew. The year of his death is unclear, but occurred in either 1848 or 1849, according to Lincoln family records. His parents lived in Coles County, Illinois, so that is most likely where he was born and died.
Family Record Written by Abraham Lincoln; U.S. Census Office, Seventh Census of the United States (1850), Coles County, IL, 82.