A statement posted on Sherwood Forest's social media sites announced the closure of the car park today (December 6)
The statement read: "We regret to say our car park will be closed to the public today, due to unforeseen circumstances.
"We are currently speaking to members of the travelling community who have moved vehicles on to our car park overnight, making it inaccessible to our visitors.
"We are trying to find a resolution, and apologise for the inconvenience in the meantime."
The car park is kept locked, so employees of Sherwood Forest are trying to establish how the travellers go on to the site.