Age: 30
Allegiance: Union
Highest Rank: Colonel
Unit: Company H, 140th New York Volunteer Infantry
Occupation: Engineer
Grantsynn was one of 37 men authorized by the Monroe County Military Committee to recruit for the 140th New York. He was 30 years old and considered "an active enterprising gentleman." He proved this to be true being named the Captain of Company H on Sept. 5, 1862. His lieutenants were Joesph S. Suggett and Charles Burtis.
Like many popular officers during the Civil War, Grantsynn was presented with a sword. The sword was given to him by the members of the Alert Hose Company, of which he was a Foreman. The presentation took place at the company's fire station and was inscribed: "CAPT. GRANTSYNN, from ALERT HOSE COMPANY."
Grantsynn served honorably through the battles of Fredericksburg, Chancellorsville and Gettysburg; but, in August of 1863 he was put under arrest and charged with making out a false return, in that he reported a private in his company as absent with leave, when he knew him to be absent without proper authority. He pleaded not guilty, but was found guilty and sentenced to be dismissed from the service. Fortunately, the commander of the Army of the Potomac, George Meade, intervened writing a letter of recommendation to the President that the sentence be commuted. In January of 1864 the sentence was changed to forfeiture of pay for six months and he was released in February.
After returning to command of Co. H., Grantsynn took leaves to visit his "dangerously ill" wife in Rochester and his family home in Illinois. He returned in time to take command of his company prior to the spring campaign season of 1864.
On May 5th, 1864, the 140th New York found itself charging Confederate earthworks at the far side of Saunders field. During the charge, Grantsynn was shot in the leg below his right knee. A witness heard him cry "My God they have knocked my leg all to pieces." The 140th was repulsed in its charge, in fact, the entire Union 5th Corps was repulsed by a determined Confederate Counter-charge led by Confederate General John B. Gordon. Grantsynn was carried to the rear on a stretcher sent for him by Lt. Henry Cribben.
The command staff of the 140th NY was virtually destroyed by the fighting in The Wilderness and Spottsylvania. William Grantsynn returned to duty on July 31st, not quite three months after his wounding to find himself the 140th's the second ranked officer by seniority. In November Grantsynn assumed command of the regiment and by January, 1865, had been promoted to Colonel.
William S. Grantsynn was mustered out in June 1865. In August he was awarded the Brevet rank of Major "for gallant and meritorious services at the battle of the Wilderness."
After the war he became the first commander of Patrick O'Rorke GAR Post, named after the regiment's first colonel, who was killed at Gettysburg. Grantsynn served as city surveyor from 1869-1875, after which he moved to Chicago, where he died in 1907.