From 1898 to 1900, Shirley served as commandant of cadets and professor of military science at
Horner Military School in
Oxford, North Carolina. He then served in the
United States Volunteers during the
Spanish–American War. After the war, Shirley worked for the
New York Central and Hudson River Railroad and other
railroad companies and for the engineering department of the
District of Columbia. He approved and promoted plans for the first
limited access highway in Virginia, extending from
Route 1 in Northern Virginia to the
14th Street Bridge in Washington, D.C. Construction on the highway began shortly after his death. This road was named as the
Henry G. Shirley Memorial Highway in his honor, and now is part of
I-95 and
I-395. ==Personal life==