Derrick F. Hamlink was a Civil War veteran who served with the 4th New York Artillery (1861-1865). He worked for the U.S. Treasury Dept. until 1868, then went into business for himself.

The collection contains thirteen documents and letters pertaining to Hamlink's career in government service and business in Washington, D.C. Some pension documents are present, but chiefly letters by various prominent people recommending Hamlink for government posts. Also present is a letter recommending his son, Newman, for a military commission.