The 57th New York Infantry was also known as Zook’s Voltigeurs. During the battle of Gettysburg, it served as a member of Zook’s Brigade in Caldwell’s Division of the Second Corps, Army of the Potomac. The 57th Mustered in from August 12 to November 19, 1861 and mustered out from July 14 to October 15, 1864. During its service the regiment lost by death, killed in action, 5 officers, 60 enlisted men; of wounds received in action, 3 officers, 35 enlisted men; of disease and other causes, 1 officer, 90 enlisted men; total, 9 officers, 185 enlisted men; aggregate, 194; of whom 28 enlisted men died in the hands of the enemy.
At Gettysburg, the infantry was commanded by Lieutenant Colonel Alford B. Chapman (August 1, 1835 - May 5, 1864). Chapman was a merchant of “fancy goods” in New York City. He was wounded at Fredericksburg and killed in action at the Wilderness in 1864. Under Chapman's command the 57th brought 179 men to the Gettysburg Battlefield and among them 4 men were killed, 28 were wounded and 2 went missing.
The 86th New York Infantry Monument is located on the right or northeast side of Sickles Road while driving northwest, 232 feet north of the De Trobriand Avenue turn. This monument in on the very western end of the Wheatfield, along the beginning of the wood line. While driving here, you would have passed the 
De Trobriand's Brigade Tablet (MN482), which is 170 feet to the south on the opposite side of the road. 
Parking is available on the side of the road at intermittently enlarged shoulders. Take care to not park on anything remotely green looking as Park Police will happily ticket you. I visited this site on Monday, July 1, 2013 on the 150th anniversary of the Battle of Gettysburg @ 5:41 PM, EDT & @ an altitude of 506 feet, ASL. As always, I used my trusty and oft abused Canon PowerShot 14.1 Megapixel, SX210 IS digital camera for the photos.
The Draw the Sword site helped out by the NPS narrative and the SIRIS site offers the following description: Granite shaft with apex cap, and bronze adornments, including a trefoil design, state tondo, and military insignia of crossed bayonets and cartridge box. The monument sits on a two-tiered base. Monument is a 14.8 foot square granite shaft with cornice and apex cap set on a seven foot square rough hewn double base. The shaft has bronze inscription tablets on all sides and a bronze cartridge box, crossed bayonets, trefoil, and state seal on the south face. The flanking markers are flat-topped with inscriptions, one foot square.
The 57th New York Infantry Monument was dedicated on October 6, 1889 by the State of New York. The sculpture is composed of granite save for the bronze relief tablet on the back of the monument which is beautiful! The monument is approximately 14 feet 8 inches x 7 feet² and the base is 15 feet x 6 feet². The monument was fabricated by Frederick & Field, a fabrication company responsible for many New York monuments at Gettysburg. There are inscriptions on all sides which read:
(Front):57th New York
Infantry,
3d Brigade,
1st Division,
2d Corps.
(Back):Engaged the enemy here
July 2, 1863.
July 3, on Cemetery Ridge,
resisting Pickett's Attack.
Total number engaged 175
killed 4, wounded 28,
missing 2.
(Right):Yorktown - White Oak Swamp
Fair Oaks -
Gaines' Mills - Malvern Hill
Peach Orchard - Antietam
Savage Station - Fredericksburg
Chancellorsville.
(Left):Gettysburg - Wilderness
Mine Run - Tod's Tavern
Auburn Hill - Cold Harbor
Bristoe Station - Petersburg
- Deep Bottom
Ream's Station
The 57th New York Infantry Monument is a contributing feature to the Gettysburg National Military Park Historic District which is nationally significant under NR Criteria A, B, C & D. Areas of Significance: Military, Politics/Government, Landscape Architecture, Conservation, Archeology-Historic. Period of Significance: 1863-1938. The original National Register Nomination was approved by the Keeper March 19, 1975. An update to this nomination was approved by the Keeper on January 23, 2004. The monument is identified as structure number MN153-B.
From the Nomination Form:
1 of 90 mns on Park honoring NY commands at Gettysburg. Marks postition taken by regiment in pm of July 2, 1863 when ordered here by Gen Zook to support front line. Located on N side of Sickles Ave at W edge of Wheatfield.
Short Physical Description:
Rough-hewn double base, 7' sq, shaft w/ cornice & apex cap. 14'8" high. Shaft: bronze inscription tablets 2'x1'5" on all sides. Bronze cartridge box, crossed bayonets, trefoil, state seal on S side. 2 Flank markers, 1'x1'x1'6", flat top w/ inscriptions.
Long Physical Description:
Monument is a 14.8 foot square granite shaft with cornice and apex cap set on a seven foot square rough hewn double base. The shaft has bronze inscription tablets on all sides and a bronze cartridge box, crossed bayonets, trefoil, and state seal on the south face. The flanking markers are flat-topped with inscriptions, one foot square. Located on the north side of Sickles Avenue at the west edge of the Wheatfield.
My Sources
1.
NRHP Nomination Form
2.
SIRIS
3.
Stone Sentinels
4.
Virtual Gettysburg
5.
Draw the Sword
6.
Historical Marker Database
7.
New York State Military Museum
8.
Find a Grave