Eshleman’s Battalion served as a member of the Artillery Reserve in the First Corps, Army of Northern Virginia. Colonel Benjamin Franklin Eshleman (March 9, 1830 – July 9, 1909) was born in Pennsylvania in 1830 and at some point relocated to New Orleans, Louisiana. He had been appointed to West Point and was still a student at the military academy when the war began. He resigned to fight for his adopted state and joined the Washington Artillery of New Orleans becoming a captain of the 4th company on 26 May 1861. Following the war Eshleman returned to New Orleans and was active in business affairs as a merchant. He died in 1909. Had he lived another year, I reckon he would have been one of the few veterans to have lived to see his own monument. There were many who survived and attended the 75th reunion and dedication of the peace memorial in 1938.
The Eshleman's Battalion - CS Brigade Tablet is located on West Confederate Avenue, on the left or east side when traveling south, on Seminary Ridge, in front of the Pitzer's Woods section. The monument faces the west and is in front of the Louisiana State Memorial. This is fitting as Eshleman Battalion consisted of four batteries of the famed Washington Artillery, of New Orleans. 
Parking can be had at the side of the road at small, intermittently placed cutouts. Please do not park on the grass, park on the side of the road. I cannot emphasize that enough! You will be ticketed. If you do not mind a very brief walk, you can also park in the amphitheater parking lot, .2 miles away and visit about 10 of these things in the immediate area. I visited this monument on Saturday, March 10, 2012 at 3:22 PM, just before the clocks were set ahead for the Spring. I was at a 591 foot ASL elevation.
Draw the Sword reports the last of these monuments were completed on December 19, 1910. For some reason, the actual dates on when these things were installed are always murky. It is amazing with all the work and effort exerted to make the Gettysburg National Military Park a reality, no one took the time to keep accurate records and correct installation dates. The work was done under the direction of the Gettysburg National Park Commission (established by the United States Department of War), after they took over the administration of the park from the Gettysburg Battlefield Memorial Association (whose funds had expired) on March 3, 1893, and whose stewardship was then transferred to the National Park Service in 1933) SOURCE.
Draw the Sword, with descriptive help from the NPS site, offers the following description: Monolith consisting of polished smooth red Maine granite pedestal with a circular base. 
On each pedestal is mounted a bronze inscription tablet describing the movements and actions of the unit. The base is 3.8 feet x 3.4 feet in diameter with a height of 5’4". The tablet measures 4 feet by 3 feet 8 inches and weighs 300 pounds with the overall weight at 3000 pounds. The tablet was constructed by Albert Russell & Sons Co. of Newburyport, Massachusetts and erected by the United States War Department. The last part is sort of correct, the Gettysburg Military Park Commission, created by the War Department actually had their workers install the monuments.
One of 64 Confederate brigade monuments. Designed by E. B. Cope and erected by the U.S. War Department. They indicate the general location of the centers of the various Confederate brigades and artillery battalions during several phases of the battle. Some of the tablets were made from melted down Civil War cannon. The tablets describe the itinerary and movements of each brigade. Erected circa 1910. The last monument was completed on December 19, 1910. The inscription on this tablet reads:
C.S.A.
Army of Northern Virginia
Longstreet's Corps Artillery Reserve
Eshleman's Battalion
The Washington Louisiana Artillery
Miler's, Squires's, Richardson's, and Norcom's
Batteries
Eight Napoleons and Two 12 pounder Howitzers
July 3 Arrived on the field before daylight and was engaged all day. Captured one 3 inch Rifle.
July 4 At 9 a.m. ordered to Cashtown to reinforce the Cavalry escorting the wagon train.
Losses Killed 3 wounded 26 missing 18. Total 45.
Horses killed and disabled 37. Guns disabled 3
There are scores of similar monuments for the various Confederate States & Union units which fought at Gettysburg. Four designs represent brigade, division, corps and army headquarters, and each has elements which identify it as Union or Confederate. Many of the tablets were created by Albert Russell & Sons Co. of Newburyport, Massachusetts and are made of granite, bronze and concrete or like this one, cast iron. All of these tablets were designed by architect E.B. Cope. He designed pretty much every tablet for both the Union and Confederate armies, each one distinct, with several different varieties. The monuments were erected just after the turn of the century during the first and beginning of the second decade of the 20th century. Each one has since been preserved or restored at least twice since the turn of the 21st century. The plaques and tablets were erected by the Gettysburg Park Commission (established by the War Department). The Gettysburg Park Commission is also referred to as the Gettysburg National Military Park Commission or the Gettysburg National Park Commission, to clear up any confusions, especially my own.
On October 1, 1898, the Gettysburg National Park Commission in a letter to the Secretary of War set gave recommendations for continuing the task of organizing and progressing the work of the Gettysburg National Military Park. Every November they wrote their annual report which outlined the work of the GNPC for that year. The following is an excerpt from that report relevant to this waymark. The link at the end of the paragraph will take you to the entire report. The method of marking the positions of troops on this field, as approved by the War Department, is to place the principal tablet or monument of each command at the position occupied by the command in the main line of battle, and to mark the several important positions subsequently reached by each command in the course of the battle by subordinate and ancillary tablets, with appropriate brief inscriptions giving interesting details and occurrences and noting the day and hour as nearly as possible. SOURCE
Information about these specific types of monuments:
BRIGADE HEADQUARTERS MARKERS (FOR UNION & CONFEDERATE TABLETS)
Brigade Headquarters (and Confederate artillery battalions, equivalent to Union artillery brigades) are bronze tablets mounted at an angle on a stone pedestal. They are the most numerous headquarters at Gettysburg, with over 70 Union and over 60 Confederate examples on the field. Union headquarters are marked with their corps or service branch symbol (like a cross, clover or crescent moon), while Confederate headquarters are simply labeled "C.S.A.". There are seventy-four brigade markers at Gettysburg honoring the AOP’s various brigades. (Other sources say there are 75). They were built by Albert Russell & Sons Co. of Newburyport, Massachusetts and Charles Kappes. The pedestals consist of sea-green granite with a square 36” x 36” base; they weigh 3500 pounds. On each pedestal is mounted a bronze tablet with rounded corners weighing 300 pounds. There are sixty-four brigade markers honoring the Army of North Virginia's various brigades. They were built by Van Amringe Granite Company (pedestals), Albert Russell & Sons Co., Newburyport, Mass (tablets) and Charles Kappes (foundations). The last was completed in December 1910. The 1910 date is disputed by other sites listing the end dates as 1912. The monuments consist of red circular Maine granite bases 34 1/2 inches diameter and weighing 3,000 pounds. On each base is mounted a 300 pound bronze tablet. SOURCE & SOURCE
The Eshleman's Battalion - CS Brigade Tablet 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 MN706.
From the Nomination Form:
1 of 63 CS Brigade Tablets in Park. Records movement of Eshleman's Battalion during Battle of Gettysburg, July 1-3, 1863. Located on E side of West Confederate Ave, N of Millerstown Rd. at Pitzer Woods.
Short Physical Description:
Bronze inscription tablets, 3'8"x3'4", mounted at a slant on circular, polished pedestal, 6'4" in circumference, 5'4" high.
Long Physical Description:
There are 64 of these bronze inscription tablets, mounted on cylindrical polished granite pedestals. They indicate the general location of the centers of the various Confederate brigades and artillery battalions during several phases of the battle. Designed by E. B. Cope. Some of the tablets were made from melted down Civil War cannon. The tablets are 3.8 feet x 3.4 feet in dimension and rest on bases that are 6.4 feet in circumference. The overall height of these markers is 5.4 feet, and they rest on either rubble or concrete foundations.
My Sources
1.
NRHP Nomination Form
2.
Stone Sentinels
3.
Virtual Gettysburg
4.
Draw the Sword
5.
Historical Marker Database
6.
Civil War Interactive
7.
Find a Grave
8.
Antietam on the Web