A warden from the Royal Borough of Windsor and Maidenhead visited the park after several caravans had left, but while some of the mobile homes were still on site.
The warden told MailOnline: “They will all be on their way soon.
“The council will be taking repossession of the recreation area.”
The travellers parked various vehicles, as well as around 30 caravans, on Windsor’s Long Walk.
The Long Walk is a 2.6 mile track that connects Windsor Castle with Snow Hill in Windsor Great park.
The cars, vans and motorhomes were in full view of the Queen’s private residence.
Signs in the area indicated that parking on-site is prohibited.
Police and council officials were called to the park on Tuesday evening and were pictured talking to members of the group.
A person, who was walking nearby, told the Mail Online they were “absolutely stunned” at the situation.
Windsor Castle is believed to be one of Her Majesty’s favourite homes and she has spent most of the coronavirus lockdown in her private apartments there.
The Castle was founded back in the C11th by William the Conqueror and has since been residence to 39 monarchs.