The popularity of state boarding schools is increasing among girls, who have led a 3 per cent rise in pupil numbers over the past year.
Numbers were up in 32 of the country's 35 schools, from 3,735 boarders in October 2006, to 3,846 boarders this year.
Parents of boarding pupils in state schools are charged only for the boarding costs, with the tuition element paid for by the state.
Paul Spencer Ellis, chairman of the State Boarding Schools' Association, and headmaster of the Royal Alexandra and Albert School in Reigate, Surrey, said: "State boarding schools are a well-kept secret no more.
"Demand is up, numbers are up, and the only limit on growth at the moment is capacity."
The Government is investing pound;20 million in improving facilities for state boarders.
Academies are also taking an interest, with a number saying they are looking at offering boarding places.