Nearly 1,000 Nottinghamshire children are in the care system, figures show.
During the first year of the coronavirus pandemic, the number of children being looked after by councils across England hit a record high, as adoption processes slowed down and youngsters spent longer in care.
Children's charity Barnardo's said the pandemic left many vulnerable children on the brink of crisis, with lockdowns and school closures meaning they often missed out on support.
That was lower than the rate across England, where 67 in 10,000 youngsters were in care on average.
In Nottinghamshire, the rate of looked-after children rose from 54 in March 2020 and was up from 52 in 2019, before the pandemic.
Of those being cared for, more than half, 580, were boys, while the largest proportion were aged 10 to 15.
Figures show 392 youngsters in the area started to be looked after in 2020-21.
The Government said coronavirus restrictions contributed to a national fall of 8 per cent in the number of children starting to be looked after, with 28,000 recorded last year.
But despite this drop, the total number of children in care rose 1 per cent across England, as the average placement increased by 79 days and adoptions fell by almost a fifth.
Lynn Perry, Barnardo's interim co-chief executive officer, said the pandemic contributed to fewer children leaving the care system, with those who turned 18 during lockdowns allowed to stay in care placements longer.
She said: “Fewer children were identified as needing adoption because there was less contact with professionals, while for many children who were ready to move in with their adoptive families, the process was put on hold.
“However, we have been concerned for a while that numbers of adoptions are reducing, and we need to do more to ensure all children who would benefit from an adoptive placement are identified and matched with suitable parents as soon as possible.”
The Local Government Association – which represents councils – said the ‘right level’ of funding was needed to allow local authorities to prevent children reaching crisis.
Anntoinette Bramble, of the LGA, said: "With spiralling demand on children’s social services and future cost pressures in children’s social care set to increase, councils still find themselves in the unsustainable position of having to overspend their budgets.
“Councils want to work with government on a child-centred, cross government pandemic recovery plan.”
A Government spokeswoman said it was levelling up outcomes for vulnerable children via a regional recovery fund for children's social care, and said councils were being given £4.8 billion in grant funding to maintain frontline services.
She said: “To give all children the best start in life, we are also championing and investing in family hubs, which offer early help to families in need.”