Officers were called to Primrose Valley at around 11.30pm following a report of a car being driven erratically.
A North Yorkshire Police spokesman said today: "Upon arrival, a man in his 20s had been detained by security staff. He was taken to hospital for treatment, where he remains at this time.
"We are appealing for any witnesses who saw a car being driven erratically around that time on the site, and anyone who may have witnessed a man being detained in the grounds of the park."
Contact North Yorkshire Police on 101, select option 2 and ask for Scarborough Serious Crime Team.
Please quote reference number 12170088431.