Officers attended the scene and traced and located a number of the group using police on foot and a helicopter.
The driver of the lorry, a 49-year-old man from Lithuania, has been arrested on suspicion of an immigration offence. He remains in police custody.
Three other men aged 20, 24 and 29, of no fixed address but believed to be from the Kurdish region of the Middle East have also been arrested on suspicion of illegally entering the UK. They remain in police custody.
A mother and three children, a young woman and a single mother with two children were taken to Harrogate Police Station and have since been transferred into the care of the local authority.
Officers still believe that there are missing people from the lorry and have received reports that around five men of Asian appearance were seen walking north on the A1 last night. Despite extensive searches, including the assistance of the National Police Air Service, they remain outstanding.
The searches for the missing men are continuing today and to assist their enquiries, officers are appealing to members of the public in the Boroughbridge area and towns and villages along the A1 corridor to report any sightings of the men.
They are also appealing to members of the public to check their sheds and outbuildings for signs of occupation in case any of the missing men have taken shelter there.
Anyone with any information is asked to contact North Yorkshire Police on 101, select option 1 and pass information to the Force Control Room.
If you have an immediate sighting of the men, please call the police on 999.