A baby boom and a housing boom are putting a strain on schools in urban areas of Devon.
Local authorities in Exeter and Plymouth have seen a sharp rise in the number of children going to primary school.
They are concerned it could lead to larger class sizes and cramped classrooms.
Devon County Council is asking the government for an extra £9m for Exeter alone.
The birth rate in the city has been rising for the past 10 years and hundreds of new homes have recently been built.
At Countess Wear the local school has brought in two temporary classrooms to cope with the increased demand for places.
Elsewhere in the county, where the use of temporary classrooms is not an option, more children are having to travel further to find a school with spare places.
Countess Wear Community School's head teacher Val Lineham said she is now taking in pupils from outside the area.
"We've traditionally been a school for our very local community," she told BBC News.
"But we're beginning to change - we're becoming a much more cosmopolitan school with children from all over the city."
Councillor Christine Channon, from Devon County Council, said that can lead to other problems, including increased travel costs for parents and the council.
"Not only that, there will be children with friends in other areas, rather than the community in which they live," she said.
Conversely, increased class sizes are not an issue in many rural areas of Devon where there are too few children on local school rolls.
However, parents in urban areas are being advised to apply to local schools as early as possible to try to ensure a place.
The Department for Education is considering Devon County Council's request for extra funding.
In a statement, Education Secretary Michael Gove said: "We will ensure that all future capital spending is focused on ensuring that there are enough school places... and to address urgent maintenance needs."