(1835 - ?)
Home State: New York
Branch of Service: Staff
Unit: Army of the Potomac
Before Antietam
He later noted 6 years service as an officer in the Austrian cavalry. On 15 August 1859, a 23 year old merchant, he arrived in New York City on the ship E.F. Gabain from Bremen. He enrolled and mustered as Captain, Company A, 8th New York Infantry on 23 April 1861, but was discharged 9 October to accept appointment as Major and Additional Aide-de-camp, USA on 20 September 1861, assigned to General McClellan's staff.
On the Campaign
He was aide-de-camp on General McClellan's staff on the Maryland Campaign and, along with Chief of Staff Brigadier General Marcy, assisted Major General Hooker at Antietam on 17 September 1862.
The rest of the War
He was discharged from the staff on 31 March 1863.
He enrolled on 30 May at Fairfax Court House, VA and mustered as Lieutenant Colonel of the 78th New York Infantry on 16 June 1863. He commanded the regiment in action at Gettysburg in July and was promoted to Colonel on 5 September 1863. He transferred to the 102nd New York Infantry in the consolidation of the two regiments on 12 July 1864 and was discharged from Volunteer service on 7 January 1865.
After the War
On 17 July 1865 he enlisted in Washington, DC as a Sergeant in Company E, 2nd United States Cavalry. He was examined by a board of officers in September 1865 in Annapolis, MD for fitness for a commission, but was found deficient. He applied again for a commission in September 1866, citing his war service and enclosing a recommendation from General W.B. Franklin. If he was commissioned, I've found no record of it: still a Sergeant, he was discharged at Fort Laramie, Dakota Territory for disability on 14 August 1867.
References & notes
His service from Heitman,1 the NY Adjutant General,2 as Herbert Hammerstein, and the Registers.3 Details from Letters Received by Commission Branch [Office of the Adjutant General, US Army], 1863-1870, online from fold3. His presence on the Maryland Campaign from General Hooker's after-action report. His immigration from Arriving Passenger and Crew Lists, 1820-1957, via ancestry.com. Personal details from family and baronial genealogies; thanks to Radisson97.
His birth parents were Baron Carl (Karl) von Hammerstein-Equord (1782-1867) and his second wife, Adelheid Charlotte von Oldershausen (1805-1886). He was adopted by his childless uncle Lieutenant General William Friedrich von Hammerstein-Equord (1785–1861), date not known.
Birth
12/20/1835; Hanover, GERMANY
1 Heitman, Francis Bernard, Historical Register and Dictionary of the United States Army 1789-1903, 2 volumes, Washington DC: US Government Printing Office, 1903, Vol. 1, pg. 989 [AotW citation 28867]
2 State of New York, Adjutant-General, Annual Report of the Adjutant General of the State of New York [year]: Registers of the [units], 43 Volumes, Albany: James B. Lyon, State Printer, 1893-1905, For the Year 1899, Ser. No. 18, pg. 493; 1901/29/p. 698; 1902/33/p. 534 [AotW citation 28868]
3 US Army, Registers of Enlistments in the United States Army, 1798-1914, Washington, DC: National Archives, 1956, Vol. 059, pg. 206 [AotW citation 28869]