United States Army reports its strength as 17,036 officers and men in nineteen regiments
The Adjutant-General of the U.S. Army reported that, as of July 1, 1859, 1070 officers and 15,966 enlisted men were in service in all branches. He wrote that 1,003 recruits were required to bring the force up to its full authorized strength. The Army fielded two regiments of dragoons, two of cavalry, one of mounted infantry, four of artillery, and ten regiments of infantry. (by John Osborne)
Thirty-Sixth U.S. Congress, Message of the President of the United States to the Two Houses of Congress... Volume 2 (Washington, D.C.: Government Printing Office, 1860), 596-597.