The site is also thought to be a bronze age burial mound.
It is thought that Thynghowe may have marked the boundary between the Anglo Saxon kingdoms of Mercia and Northumberland.
However, it may date back much further, as 'howe' is a term often used to indicate a prehistoric burial place.
"It's a very exciting find," said Stuart. "We're talking about 4,000 years of history in the heart of Sherwood Forest."
This and other Viking meeting place locations were chosen for their acoustics.
Stuart said a voice spoken at the meeting place in the Birklands can be heard from hundreds of yards away.
Research has found that the site was used for centuries.
"We've got documentary evidence that people met there right up to the 1800s. Local people were still meeting up there and raising each others spirits 200 years ago," said Stuart.
The site has now been recognised as a national rarity by English Heritage and added to their National Monument Record.
Funded by local donations The Friends of Thynghowe have been working hard to increase public awareness of the site's history.
"We've put a marked trail in, we've produced leaflets and booklets," said Lynda. "We've done a lot of work to promote this."
THE THYNGHOWE
Members of Friends of Thynghowe in the Birklands
The Thyghowe is one of only a handful of such sites known in the British Isles
It was a landmark where people came together to resolve disputes during the Dark Ages
It may also have marked the boundary between the Anglo Saxon kingdoms of Mercia and Northumberland
'Howe' is a term used to indicate a prehistoric burial place
Every April they also host an annual walk around Thynghowe, explaining all the history of the site. In 2011 it will be held on 16 April.
And they are now putting in an application for Heritage Lottery funding to develop 'trail tales' for school children.
"So they can start to connect these exciting stories with the real history of Sherwood Forest," said Lynda.
"This is our real cultural heritage," added Stuart. "We love Robin Hood, we love the Major Oak but this is real history. This represents families that have lived in the area and it belongs to the people of the area."
A topographical survey using total station and GPS will take place from 17 to 22 January 2011.
Archaeologists from University College London will also be present using magnetometry to reveal the extent of the site and what may be beneath the ground.
Friends of Thynghowe and interested members of the public are invited to come along and help on Thursday, 20 and Saturday, 22, 9.30am - 12.30pm and / or 1.30pm - 4.30pm. Booking is essential.
If you are interested in attending on either or both of these dates please contact Alex Price, the Local Improvement Schemes Project Officer on 07753625571.
http://news.bbc.co.uk/local/nottingham/hi/people_and_places/history/newsid_9155000/9155982.stm