Newcomer, Henry Clay was born on April 3, 1861 in Upton, Pennsylvania, United States. Son of David and Mary Shelley (Funk) Newcomer.
Graduated from the United States Military Academy, 1886, Engineer School of Application, 1889.
Commissioned Second lieutenant engrs., July 1, 1886. First lieutenant, July 23, 1888. Captain, July 31, 1897.
Major, April 23, 1904. Lieutenant colonel, February 9, 1910. Colonel, May 2, 1915.
Brigadier general, August 8, 1918-February 5, 1919. Assistant to Colonel Mendell, San Francisco, California, on fortification work, 1889-1892. Instructor and assistant professor engineering, United States Military Academy, 1892-1896.
In charge river improvements, 3d District, improvement Mississippi River, 1896-1900, and Little Rock (Arkansas) District, 1898-1900. Assistant to engineer commissioner of District of Columbia, 1900-1903. Commanded Company E, 3d Batln.
Engineers, Washington Barracks, District of Columbia, 1903-1904. Member Board Engineers for Rivers and Harbors, 1904, 1908-1909, and 1910-1919. Division engineer Central Division, 1910-1914.
Assistant to chief of engrs. in charge River and Harbor Section, 1916-1918. Assistant director Chemical Warfare Service, August 6, 1918-January 6, 1919. In charge harbor improvements, Honolulu (Hawaii) District, department engineer Hawaiian Department, and commanding 3d Engineers, 1919-1920.
Clubs: Army and Navy (Washington), Oahu Country (Hawaii).
Married Rebecca E. Kosier, of Byron, Illinois, December 29, 1886 (died March 31, 1913). Married second, Mistress.