Schools in Derbyshire were forced to close after travellers parked their caravans and motorhomes on playing fields.
Pupils at three schools in Long Eaton were told lessons were cancelled and only those with exams should attend. One pupil said she was worried the travellers, who set up camp on Tuesday evening, would "wreck the sports field" that the schools shared, the Nottingham Post reported.
Police guarded the main gates to the playing fields, which had been closed for the majority of the day. Around 1,315 pupils at the schools - Parklands Infant and Nursery, Wilsthorpe Community and Harrington Junior - were affected by what one parent called a "disruption".
Mother-of-four Ruth Jenkins told the local paper: "It is just the disruption, not only to the children, but to parents who have got to take days off to look after their kids.''
But one traveller, "John", said the group had parked there due to frustration at a lack of permanent traveller sites provided by the county council, according to the BBC.
"We're sick of this happening seven days a week," he said. "As soon as we leave and go somewhere else, we'll have the same thing again."
All schools opened as normal on Thursday.
A Derbyshire Police spokesperson confirmed Harrington Junior School had reported the travellers to the police on Wednesday. The travellers left at noon after police issued a Section 61 notice of the Criminal Justice and Public Order Act, which gives police powers to remove trespassers on land.
The travelling community has been catapulted into the limelight by Channel 4's My Big Fat Gypsy Wedding series - which has been blasted by the community for being racist and abusive.