The 124th New York Infantry was also known as The Orange Blossoms. The unit was officially mustered into United States Service on September 5, 1862, by Col. Augustus van Horne Ellis, the regiment was made up of volunteers from the surrounding towns and a core of veterans from the 71st New York State Militia. During the battle of Gettysburg, it served as a member of Ward’s Brigade in Birney’s Division of the Third Corps, Army of the Potomac, a Fighting 300 Regiment. The regiment was commanded by Colonel Augustus Van Horne Ellis (1827-1863), a sea Captain from New Windsor. A.V.H. Ellis was born in New York City and educated in the city's public schools. He later attended Columbia University. Prior to the outbreak of the Civil War, he was a lawyer in New York City. On September 5, 1862, Ellis became the first colonel of the newly raised 124th New York Infantry. The regiment had been recruited from mainly Orange County. After training and drilling, the 124th joined the Army of the Potomac in Northern Virginia. Ellis and his men saw no heavy fighting until May 1863. Then, at the Battle of Chancellorsville, he gave the 124th the nickname of "Orange Blossoms". He admonished the soldiers, "Let the girls of old Orange hear a good report of this day's work." The regiment lost 40% of its strength at Chancellorsville.
In the thick of the fighting by the Devil's Den, Colonel Ellis ordered the staff's horses brought up and he, Major James Cromwell and Adjutant Henry Ramsdell mounted. When a captain protested that they were making targets of themselves Major Cromwell replied, "the men must see us today." Both he and Colonel Ellis were killed, but the 124th bought an hour's time for the south flank of the Army of the Potomac. Lieutenant Colonel Francis M. Cummins (1822-1884) took command of the regiment despite also being wounded.. Under their collective commands, 279 men were engaged @ Gettysburg and among them, 28 were killed, 57 were wounded and 5 went missing. All totaled during service, the regiment lost by death, killed in action, 9 officers, 93 enlisted men; of wounds received in action, 2 officers, 45 enlisted men; of disease and other causes 1 officer, 94 enlisted men; total, 12 officers, 232 enlisted men; aggregate, 244; of whom 11 enlisted men died in the hands of the enemy.
The 124th New York Infantry Monument is located on the straightaway portion of Sickles Road that comes out of the serpentine section which wraps its way to the top of Devil's Den. The monument is on the right or east side of the road if traveling north. The monument is the last of the monuments along the ridge at Devil's Den and is in a small clearing forty feet off of the road. 
Parking is available up here at large shoulder areas on the right side of the road to the rear or south of the monument about 170 feet away. 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 @ 4:53 PM, EDT & @ an altitude of 542 feet, ASL. As always, I used my trusty and oft abused Canon PowerShot 14.1 Megapixel, SX210 IS digital camera for the photos.
There is another monument to this regiment also called the 
124th New York Infantry Monument which marks the location occupied by a remnant of regiment on July 3, 1863. This monument is located on the north or left side of Pleasanton Avenue if traveling east, due north of the Pennsylvania State Monument, (which is located on the east or right side of Hancock Avenue), near the Hummelbaugh farm & East of Hancock Avenue.
The Draw the Sword site helped out by the NPS narrative and the SIRIS site offers the following description: Full-length bronze figure of a commanding officer, Colonel A. Van Home Ellis, dressed in uniform with scabbard at proper left side, stands atop granite monument giving history of 124th New York Infantry. The monument marks the position held by the 124th Regiment on July 2, 1863, and the statue is the likeness of Col. A. Van Home Ellis, killed at battle here. Monument is a granite shaft topped with a seven foot stone statue of the regiment’s commanding officer set on a 4.5 foot square base. The shaft has a bronze tablet on the north and a bronze tablet with the state seal on the south. Flanking markers are one foot square.
After the war, the citizens of Orange County raised money to erect a monument to the 124th Regiment at Gettysburg. Dedicated on July 2, 1884, it was the first regimental New York monument placed on the field. Located on Houck's Ridge where the regiment stood above the triangular field, the monument has a life-sized statue of Colonel Ellis, standing with his arms folded gazing calmly ahead. It is the only official full-sized statue of a Union regimental commander at Gettysburg. While the sculpture is bronze, the monument is composed of St. Johnsburg Vermont granite which rests on a natural boulder. The soldier and the monument are approximately 16 feet 2 inches x 3 feet 8 inches² and the base is approximately 1 foot 6 inches x 4 feet 5 inches². The monument was sculpted by Maurice J. Power (1838 - 1902) and fabricated by Peter B. Laird. There are inscriptions on all four sides which read:
i>(Front):124th New York
Infantry.
2nd Brigade 1st Division
3rd Corps
July 2nd 1863.
(Back):The Orange Blossoms
went into action on
this spot with
18 officers and 220 men.
Lost in killed and wounded
7 officers and 85 men.
——•——
Mustered in-Sept. 5, 1862.
Total Enlistments - 1320.
Total Losses 516.
Mustered out-June 2, 1865.
(Right):KilledCol. A. Van Horn Ellis
Captain Isaac Nicoll
Sergt John D. Drake
Corpl Jacob Lent
Priv William Lamereaux
Priv Benjamin F. Flagg
Priv James Roke
Priv William H. Cox
Priv James E. Homan
Priv Charles Edwards
Priv James Partigton
Priv William Whan
Priv John Carroll
Priv Cornelius S. Allen
Priv George H. Stephens
Priv Ambrose S. Holbert
Priv Walter BartonOur Comrades They Died
For Their Country.
(Left):KilledMajor James Cromwell
Lieut J. Milner Brown
Corpl Orlando U. Knapp
Corpl Isaac Decker
Priv Harrison Storms
Priv Robert J. Holland
Priv John Glanz
Priv James Pemberton
Priv John W. Leeper
Priv James B. Moore
Priv Hezekiah Harris
Priv John Scott
Priv Amsey W. Quick
Priv Isaac G. Gillson
Priv William D. Dawkins
Priv William CampbellOrange County's Tribute
To Her Brave Defenders.
The 124th 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 MN129-C.
From the Nomination Form:
Marks position held by 124th New York Infantry on July 2, 1863 when attacked between 3:00 & 4:00 pm. 1 of 90 in Park to NY commands. Position marker marks location occupied by remnant of regiment on July 3, 1863. Locate E of Hancock Ave.
Short Physical Description:
Mn, 2 flank markers, 1 position marker. Base, 4'5" sq. Granite shaft topped w/ stone statue of regiment's commanding officer, 7' H. Shaft has bronze tablets, 2'7"x3'8" on N face. Bronze tablet w/ State seal, 2'4"x3'4", on S face. Flank marker, 1'x1'.
Long Physical Description:
Monument that has two flanking markers and one position marker. Monument is a granite shaft topped with a seven foot stone statue of the regiment’s commanding officer set on a 4.5 foot square base. The shaft has a bronze tablet on the north and a bronze tablet with the state seal on the south. Designed by Maurice J. Power and R. D. Laird. Flanking markers are one foot square. The position marker is located east of Hancock Avenue.
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. 7.
Wikipedia