GPR helps detect US Civil War artifacts
close X
Nav Menu

GPR helps detect US Civil War artifacts

By Chip Langman

A board member of the Lexington Missouri Battlefield Foundation describes his experiences using the LMX200 GPR to uncover non-metallic US Civil War artifacts, including cannon “grapeshot” and a 300-year-old road.

Several years ago, my wife, Sharon, and I moved to a small Civil War town on the banks of the Missouri River in Lafayette County, Missouri. We purchased a historic 1870’s home that was built on what was the southeast entrenchments of Colonel Mulligan’s United States troops during the September 1861 Battle of Lexington. Following that battle, the property was bought and established as part of the campus for the Central College for Women – which folded into the Central Methodist University in the early 20th century. Our State Street house was a never-ending treasure-trove of local lore – tales from people in town who had lived in or visited it over the last century, and a point of discussion anytime the subject of ghosts came up (spoiler…we never saw or experienced anything out of the ordinary).

GPR data
Figure 1
Original battlefield map of the Battle of Lexington, Missouri. The author’s former house was later built in the area of the battle.

While we automatically assumed the house held bountiful amounts of gold buried in the walls or yard (since EVERY house in Missouri was, at one time or another, a hideout for Jesse James), our questions about the property were a little more in-depth and specific. As a Civil War nerd (more specifically, an artillery geek), I wanted to know if our little 0.49 acres was the scene of any cannon action during the Civil War.

Enter the picture the husband-and-wife team of Jackwick Metal Detecting. Chadwick and Jackalyn Oldham agreed to come out on a near single digit degree day to analyze our property and see if they could locate any artifacts or areas of interest that might tell a story. Within minutes of arriving and beginning their detecting, Jaci, using a metal detector, located a dropped rifled musket round of military vintage right in our front yard. I cannot describe the off-the-chart excitement that I experienced when they pulled that lead bullet from the ground. As the day progressed, it became obvious that Chadwick and Jaci weren’t treasure hunters…or your run of the mill metal detectorists…they were genuine historians.

Over the course of the next several years we became close friends with the Oldham’s – and asked them back to Lexington almost monthly to not only search other permissible properties, but to help document their findings and carefully create accompanying GPS points. Discovering not only what, but where and at what depth these items were, assisted in adding a little more tightly woven fabric to the somewhat loosely knitted story of the Battle of Lexington.

Ordinarily, following each battle, officers on both sides would put pen to paper and write out their account of the action they encountered to report back to their respective commands and governments. Lexington was different, in that only the (pro-Confederate) State Guard would produce after-action reports. Obviously, things can get a little convoluted when you only have one side of the story.
As these findings continued to brew our interest for even more understanding – the Oldhams introduced us to their latest Ground Penetrating Radar (GPR) equipment, an LMX200 (Figure 2).

GPR data
Figure 2
Chadwick Oldham of Jackwick Metal Detecting with his LMX200 GPR system.

These instruments can produce images of the subsurface and provide invaluable and undisturbed depictions of an item and its immediate surroundings without even digging it up. For example, the GPR line with the response from the buried grapeshot is shown in Figure 3. This is some pretty high-level nerd research stuff!

GPR data
Figure 3
Raw GPR data image showing the high reflectivity target that was excavated and revealed to be grapeshot.

Over time, we were able to more closely identify where skirmishing occurred on the northeastern part of the battlefield – by tying together a piece of canister from a 12 lb. artillery piece and clusters of spent musket rounds, also known as grapeshot (Figure 4).

GPR data
Figure 4
Jackalyn Oldham of Jackwick Metal Detecting holds a stacked grapeshot from a 12 lb. canister shot out of a cannon (left), found with the LMX200 GPR. The spent rifled .69 caliber “Minnie” musket bullet round (right) was found with a metal detector.

This location is near where the US War Department’s early 20th century map depicted the third fighting location of Bledsoe’s State Guard battery (coincidentally, this battery had the only 12lb cannon at the battle).

Fast forward a couple of years and a thousand miles. Sharon and I embarked on yet another adventure by moving to Adams County, PA. Here, we purchased a small colonial era farm which played part in another Civil War Battle…Gettysburg. In like fashion, we twisted the Oldhams’ arms to come out and replicate the efforts that proved so decisive in Missouri.

We learned that our property served as the staging area for one newly promoted Brigadier General George Armstrong Custer’s Michigan cavalry brigade on July 2, 1863. Our big question was where exactly was the original road that cut through our property that served as not only access for Custer’s famed Hunterstown Charge – but also the 300 years’ worth of travelers who traversed this part of the Beaver Dam Creek (Figure 5). Low and behold, it was an easy find for the Oldhams and their GPR machine (Figure 6).

GPR data
Figure 5
Area where a historic road used for 300 years in the Beaver Dam Creek area is located. This area was surveyed with the LMX200 GPR to determine the exact position of the road in the subsurface.

GPR data
Figure 6
1.2-to-1.5-foot GPR depth slice showing high amplitude (red) reflectors interpreted to be the historic Beaver Dam Creek Road.

It was not exactly where locals remember their grandparents’ description…but instead, solid evidence of a nearly forgotten road that linked populated founding cities like Philadelphia with the remote mid-18th century western frontier.

As technology progresses and lands in the hands of capable and thoughtful historians like Chadwick and Jackalyn Oldham, they will be able to continue providing a better understanding of our past.

Story by Chip Langman. He and his wife operate Cavalry Ridge Farm in Gettysburg, PA. and continue to serve on the Board of the Lexington Missouri Battlefield Foundation.

Photos and GPR data courtesy of Jackwick Metal Detecting –

For more of the Oldhams’ adventures with the LMX200, read our previous article on how they found buried family treasure –

Sensors & Software loves to share our customers’ GPR stories! Customer stories, like this one, are always popular, but note that the details and descriptions are those of the authors and Sensors & Software has not edited except for typographical errors.

If you have a GPR topic of interest to share, please contact us and submit your suggestions.