The kings and queens of Ulster resided in this location for centuries.
Archaeologists have recently been attempting to put together the exact layout of the structure and the time period during which it was occupied.
The site may have been occupied as early as the 4th Century BC, according to the physical evidence that has reportedly been discovered.
In 2020, the location underwent magnetic gradiometry and electrical resistance surveys, which marked a significant advancement.
This revealed clues to the existence of enormous Iron Age temples and other religious complexes.
This month, academics from Queen's University, Belfast, went back to Navan Fort to participate in an excavation where they think they found proof of this.
The "Ceremonial Center"
On the hilltop site, four new trenches have been opened for this year's dig.
Dr. Patrick Gleeson, an archaeologist, said: "What we are learning is that some of the early periods here are actually very exceptional.
They are possibly unique in terms of the sophistication of some of these monuments on this island; we only know of one or two other parallels.
Iron Age massive constructions are extremely hard to discover, especially given their Iron Age date.
The Iron Age spanned around 800 BC to 43 AD, when the Romans invaded Britain.
Dr. Gleeson told BBC News NI he thought the dig's results were noteworthy, but they will need to be taken away and carefully examined.
He stated, "Right now it appears that we have an entirely new early to mid-Iron Age monumental horizon to the complex."
"Everything that you see on the site today dates to roughly 95 BC or later.
'What we have found is that some of the buildings that were unearthed in the 1960s sit within a massive sequence of timber palisaded enclosures from the 4th to the 1st Century BC in terms of dating range.
They are made up of substantial structures perched on a hilltop, enclosed by a huge 160-meter-diameter figure-of-eight enclosure, with enormous timber posts outlining the perimeter of the site.
Site A refers to one of the ditches.
It is a mysterious construction, according to Dr. Gleeson.
"We would anticipate a ring barrow to be a burial monument, but it appears to be a ring barrow instead.
In light of this, we are looking into the monument's bank and ditch. Therefore, it might have been employed for industry, post-medieval activities, or even early medieval residential constructions.
The discovery, according to Dr. Gleeson, will advance "our understanding of the site."
"But it also confirms some of the suspicions that have been growing over the last few decades that, rather than this being a residential center of the Kings of Ulster, it actually appears to be a ceremonial center of paramount ritual and religious significance," he continued.
In the medieval era, it eventually changes into a more residential and symbolic center. That enables us to contextualize it both in an Irish and a north-western European perspective.
"Really thrilling"
Navan Fort is currently on the tentative list with five other Royal Sites of Ireland, and it is hoped that one day it will be added to the list of World Heritage Sites.
The participants in the dig are aware of the importance of the initiative.
As an excavator on this year's dig, PHD candidate Louise Moffett is holding a shovel in her hand.
She exclaimed, "It's extremely thrilling.
"Most of the sites I've worked on in the past nobody has heard of, but now everyone knows the site that I've dug at," the author said.
"Right now, I'm digging a feature out of this trench's back.
"We found some of the edges, so it's basically about finding those edges to work out the circumference of the feature then following them down until you find the base," she continued.
"However, you only partially excavate it, leaving us with a flat surface known as a section. This allows us to determine whether the feature is made up of several layers that have been added over time, or if it is just one deposit.
Dr. Cormac McSparron is perched on the edge of the trench, a sketchbook in his hand. Later, his sketches will help with the creation of three-dimensional models of discoveries.
This is only a basic sketch design that is a little bit below publication level, he explained.
"I'm just going to note all the numbers. It is merely a brief plan that will be included in the 3D model later.
The trenches will be filled in once the digging is finished.
Gaps in our understanding of this incredibly extraordinary place are hoped to follow.