1st Battalion, New York Sharpshooters
Major W. S. Rowland received, October 10, 1862, authority from the War Department to recruit a regiment of sharpshooters in the States of New York and Pennsylvania; the regimental organization failed and only a battalion was recruited, which was finally organized consisted of four companies, the 6th, 7th, 8th and 9th; 
The New York State Military Museum website has a unit history project page for the 1st Battalion, New York Sharpshooters.
The Civil War in the East website gives a timeline for the involvement of 1st New York Battalion Sharpshooters in the war.
The 1st Battalion, New York Sharpshooters mustered in by companies. It mustered out 6th, 7th and 8th Companies July 10, 1865, 9th Company August 5, 1863
Book: NO WORD OF THEM: First Battalion New York Sharpshooters, 1862-1865 author: John Bennett http://1stnyss.blogspot.com/2008_03_01_archive.html
Companies in this Regiment with the Counties of Origin
Men often enlisted in a company recruited in the counties where they lived though not always. After many battles, companies might be combined because so many men were killed or wounded. However if you are unsure which company your ancestor was in, try the company recruited in his county first.
The regimental organization failed and only a battalion was recruited, which consisted of four companies, the 6th, 7th, 8th and 9th.
Sixth Company; - Flank Company, 108th N. Y. Volunteers: This company was organized and recruited at Rochester, under Capt. Abijah C. Gray and principally recruited from Ulser county.
Seventh Company;- Company L, 112th N. Y. Volunteers: This company, Capt. Joseph S. Arnold, was organized at Jamestown. It was recruited principally at Ellicott, Kian-tone, Busti, Ellington, Ellery, Carroll and Jamestown and principally recruited from Chautauqua county. The company was commanded by Capt. Clinton Perry.
Eighth Company - This company was recruited by Capt. Edward G. Robison, at Buffalo, Hudson and Chatham; the men enlisted by Lieut. M. P. Pierce, at Buffalo, Hanover and Aurora and principally recruited from Erie county.
Ninth Company - Recruited by Capt. Thomas S. Bradley, at Albany, Hudson, Canaan, Hinsdale and New Lebanon, and organized at Camp New Dorp, S. I. and principally recruited from Albany county.
Tenth Company - Capt. Charles M. White, was originally intended for a service of nine months, and organized January 13, 1863; April 21, 1863, the term of service was changed to three years; the company was, however, not completed, and the men enlisted were, June 9, 1863, transferred to the 9th Company, the Enfants Perdus. and the 178th N. Y. Volunteers. The officers recruiting for the company were Lieuts. Ernest Blackmere and Frank A. Tease.
1. Civil War Soldiers and Sailors System has the information listed above and may have additional historical information. Searches can be made by name of a soldier or sailor. Information about cemeteries battles, prisoners, medals of honor and national parks is also included.
2. Phisterer, Frederick. New York in the War of the Rebellion, 1861 to 1865. Albany, New York : J.B. Lyon, 1912. Google Books, other libraries with this book, FHL Book 974.7 M2p; FHL Film 1486494-6
3. The Union Army : a History of Military Affairs in the Loyal States, 1861-65, Records of the Regiments in the Union Army, Cyclopedia of Battles, Memoirs of Commanders and Soldiers, Reprint of original published: Madison, WI.: Federal Pub. Co., 1908. Other libraries with this book,FHL Books 973 M2ua, vols. 1-9
4. Frederick Henry Dyer, A Compendium of the War of the Rebellion, (Des Moines, Iowa: Dyer Publishing Co., 1908), as cited at Civil War Soldiers; Sailors System (database on-line).
5. New York State Division of Military and Naval Affairs. "Unit History Project : New York State Military Museum and Veterans Research Center at citing Frederick Phisterer, New York in the War of the Rebellion, 3rd ed. (Albany, N.Y.: J. B. Lyon Company, 1912).
6. Hawks, Steve.The Civil War in the East. Database.
- Frederick Henry Dyer, A Compendium of the War of the Rebellion, (Des Moines, Iowa: Dyer Publishing Co., 1908), as cited at Civil War Soldiers and Sailors System (database on-line)
2.↑ New York State Division of Military and Naval Affairs. "Unit History Project ; in New York State Military Museum and Veterans Research Center at http://dmna.state.ny.us/historic/reghist/civil/infantry/.htm citing Frederick Phisterer, New York in the War of the Rebellion, 3rd ed. (Albany, N.Y.: J. B. Lyon Company, 1912).
3. Hawks, Steve.The Civil War in the East. Database. http://www.civilwarintheeast.com/