You should see if any of your nearest universities have Anthropology departments. My school had a whole sub department for Archaeology and my professors would have been stoked to have a local come to them with an opportunity to do field work. It’s great practice for the students. If you’re open to it, they can do a full excavation. Or if you prefer no digging they may be able to map out the area with ground penetrating radar. But if you let them dig they’ll probably be better able to get you the information you’re seeking.

Give the Georgia State Historic Preservation Office a call at 770-389-7844. They should be able to help get you in touch with an archaeologist. This is the office that is usually in charge of keeping a record of all archaeological sites within a state. Here is their website https://georgiashpo.org/

(FYI: Archaeology is a subfield of anthropology in the US)

Archeologist here - specifically a bioarcheologist with a background in CRM (culture resource management, the non academic branch of archeology). I have worked on large native cemeteries and standalone native burials, as well as pauper cemeteries. Further, I've worked on plantations and slave villages.

First, it's going to be hard to get a CRM company out there without paying them. CRMs are for profit (usually, at least in California where I live) so they can't afford to pro Bono work. Since you are on private property, there's no chance of getting government money to pay for an excavation.

Second, in the absence of historical documentation there is no way to tell if this burial is a slave burial, short of an excavation. While I have not worked on a slave graveyard (my work was with native burials and 19th-early 20th century pauper cemeteries), my guess is that if the unmarked grave was near another burial with an elaborately carved headstone, you're looking at the owners plots. Again, no experience with slave burials specifically, but experience with working on plantation sites and slave 'villages' tells me that a slave would probably have not been buried near the owners. If I had to venture a guess, I'd say that there is a greater possibility that it MAY be a child burial, due to the other nearby headstone belonging to a woman who died in childbirth, and the stone in question being unmarked. Obviously, this is just an educated guess, so please take this with a massive grain salt. If you can find more info on the woman with the marked stone, you might be able to see if her child also died, which would make my hypothesis a little stronger (but still by no means correct or even overly reliable)

Third, best people to contact would be your local state historical preservation office (SHPO). They probably won't be able to help you with excavation directly, but they might be able to tell you who can.

Finally, I can't believe that any anthropologist would tell you to do the excavation yourself. Please don't. Echoing what others have said, this is a big no no in archeology. Provenience (or the exact placement of artifacts or remains within a historical site) is everything in archeological data collection. That being said, your best hope for an excavation is to get some university archeologists out there. As others have said, I'd recommend contacting the head of the department directly to see if you could get some grad students or even an undergraduate who would be interested in a cool project.

You've gotten some very good advice about anthropology/archaeology, so I thought I'd give you some public history perspective so you can come at this from other angles. (I work in public history/museums.)

In your shoes, some of my first steps would be to confirm if the family that owned the land did actually own (or lease) enslaved people. This can be a tricky thing to confirm; as others have noted, enslaved people were counted in different ways over different census periods. You can start by mapping out the owners of the property from 1790-1860 and finding them in each census year. You'll want a basic genealogy tree of the family to at least indicate who ended up owning the land from generation to generation, which will be helpful when you are looking for census records and for your next step. Of note: Georgia also conducted a state-specific census, which may have included information different from the national census. More on that through the Georgia Archives: https://www.georgiaarchives.org/research/census_records

Census records only cover a specific point in time in a year ending in 0, so there's also possibilities in between those years. The next thing to look at will be any kind of wills or probate records for immediate family members who died during those years. It was not uncommon to list enslaved people among the "possessions" gifted or deeded to a specific family member. Sometimes this is a basic description, and sometimes it's more detailed. An example: within my own family there is a record of my great-x-5-grandfather leaving an enslaved 17yo girl named Permelia to his widow. (Note: all of the above can be carried out by a competent freelance genealogist, if you'd rather hire someone to do it.)

If the family did also have a long history within the area (which it sounds like), your local historical society may have more information on them. Start with your town, and then go to county level. The Georgia Archives has a nice directory of local history organizations that may prove helpful: https://www.georgiaarchives.org/ghrac/directory. A longtime landowning family may appear in published town histories, published genealogies, and more. If you're really lucky, you may find actual papers belonging to the family that would detail more.

If you're able to prove that the family did enslave people, then you have corroborating evidence that there may be the grave of an enslaved person on the property. It seems to me unlikely that an enslaved person would have been buried in a family plot, but you never know. If the family did enslave people, there may also be other traces of that history on the land that would prove interesting under archaeological examination. The Georgia State Archaeologist should have some kind of idea of what an excavation would look like, whether it's a good student project, etc. It seems likely that they will also have experience in finding and handling traces of enslavement.

There are museums and historic sites that are doing similar work right now, and if you can find one local to you they may have additional advice. I don't know the Georgia history landscape very well, but there's likely to be someone nearby. I'd look on their website for evidence that they're taking the history of enslavement seriously before reaching out; there are a number of museums & historic sites still hewing to old and simplistic interpretation rather than really grappling with their history. So you'll want to find clear, direct evidence on their website that they are interpreting and engaging with their site's history of enslavement through programs, archaeological work, ongoing research, etc.

You could do some genealogical research online to figure out whether the young woman buried there was a slave. The census noted a person's race, so if a white Sarah Mapp shows up living there in those years, there would be your answer. You can make a free account on FamilySearch.org and search their census records from 1840 and 1850.

The 1840 US Census only named the head of household, so if there are other names on the headstone you might be able to determine what Sarah's father or husband's name was and look for that in the census records of your town. Everyone else in the household was just counted, with race and free status noted. She would only be counted in that census if she was born before the time they took the census.

You'd have better luck with the 1850 census, which named all of the white members of the household. Slaves were only counted, not named. Since you know the exact property that the Mapps should be living at, that could help you narrow it down. Most records, including the US Census records, are free to view on FamilySearch.org. (Occasionally for other types of records they will tell you the record exists but redirect you to a paid site like Ancestry.com to view them, but that shouldn't happen with US Census records.) If Sarah Mapp showed up living at the house around the right age, that would mean she was white. If not, she might have been a slave.

I want to chime in with a slightly different tack: you should be consulting an attorney who specializes in real estate law before proceeding any further.

You're starting to get into a grey area of property law here. In fact, in several states - Virginia, I'm thinking of you - gravesites on private property have very distinct access rights and can complicate the title.

So prior to doing any more work on the archeological side of things, please protect yourself by sitting down with someone who is licensed and knows Georgia title law to discuss your situation and what you'd like to do. Any attorney worth their salt will tell you getting called in early for a possibly overcautious consult is vastly preferable to the alternative.

As far as the history, awesome sauce to you for being so proactive, and unfortunately I don't have anything to add on that front - you've gotten some high quality responses so far!

My family's farm had a small family cemetery, as well graves that were known to be the enslaved people of the first property owner that settled the land, before my family purchased it way back when. Family had good documentation over the years about this, and family was the only owner of this land for a few generations. You may find that there is information about your land, the families that lived there, and perhaps the enslaved people that lived and worked there as well. My family, for example, kept meticulous family records, and extended family all around owned neighboring land. So the local library has bound family history details and sources. Additionally, if anyone wanted even more information, and contacted our family, interested in the history of that cemetery or land, most of us would be happy to assist. Our family, sadly, sold that property a few years ago. I remember, as a child, helping my grandparents restore the cemetery and keep it cleaned out. I had a detailed oral history of the people who are buried there, as well as which graves were those of enslaved people, what we knew about them, the fact that the enslaved people were buried in a specific area (and possibly why).

Researching the family history of the landowners in the local library, and asking descendants (both landowner, and possibly descendants of any enslaved people if generations continued to live locally) may help you not only verify if those are "slave graves" but also might lead to any documented or oral history that might survive.

Hey first of all, I'm glad to see from you other comments that you are all on board with going about this in the proper manner. I saw that you mentioned you may do a memorial of some sort and clean the place up around it. Great idea, but I would say be careful if you are digging at all as graves can have other graves near them if the area was used as a cemetery. Grave stones can be taken away/damaged, and many may have been unmarked graves. Just a heads up!