Some 525 children were being looked after by Blackpool Council last year, according to new statistics – a five year high.
The resort also continued to have the highest rate of looked-after children than any other local authority, the new government figures said.
For every 10,000 youngsters in the resort last year, 184 were in care.
Middlesbrough had the second high rate with 137. The lowest, with 36, was North Yorkshire.
Last month, The Gazette revealed how the cost of the council’s children’s service had risen from £35.7m last year – when the department overspent by £5.4m – to £38.4m this year.
Coun Graham Cain, the cabinet member responsible for children’s services, said: “When they are in our care, we automatically become that child’s legal parent and it is only fair that we treat and look after them as we do our own children.
“With that comes extra costs in supporting them, keeping them safe and providing them with the tools to not be left behind.”
The council has given more support for families through Better Start, and encouraged more people to foster or adopt, but concern has been raised about the cost of placements outside the town.
Sir James Munby, the top family court judge in England and Wales, recently highlighted Blackpool as he raised concerns about a shortage of secure accommodation units in England for children.
He said the problem had led to social services bosses trying to place children in their care in units in Scotland, and highlighted the issue in a written analysis of cases involving two children.
Sir James did not identify the pair, but said the cases involved Blackpool Council, and Cumbria County Council.
STATISTICS: LOOKED-AFTER CHILDREN, FROM THE DEPARTMENT FOR EDUCATION
Blackpool (Number of children looked after by the local authority)
2013 - 480
2014 - 445
2015 - 455
2016 - 470
2017 - 525
Blackpool (Rate per 10,000 children aged under 18)
2013 - 166
2014 - 153
2015 - 158
2016 - 164
2017 - 184
England (Rate per 10,000 children aged under 18)
2013 - 60
2014 - 60
2015 - 60
2016 - 60
2017 - 62
North West (Rate per 10,000 children aged under 18)
2013 - 79
2014 - 81
2015 - 82
2016 - 82
2017 - 86