More unaccompanied asylum-seeking children are being looked after by the council in Lincolnshire, figures show.
The Children's Society said it is essential these children who arrive alone, often after a "traumatic and dangerous" journey, get the proper support and protection they need from local authorities.
Unaccompanied asylum-seeking children often present themselves at points of entry into the country in their own right and are separated from both parents or any other responsible adult.
Figures from the Department of Education show 36 lone asylum-seeking children were in care in Lincolnshire on March 31, up from 26 the year before.
Kent looked after the largest number of asylum-seeking children in England at this time, with 370 in care in the area. It was followed by Hillingdon with 139 children and Manchester with 138.
Across the country, 5,570 unaccompanied asylum-seeking minors were being looked after by local authorities at the end of March – the largest number since records began in 2004 and up 34% on the year before.
The figures show the ethnicity of asylum-seeking children in care has changed over time, with nearly half (45%) from "other ethnic groups" – up from 35% in 2018.
About 24% were Asian or Asian British, while 23% were black, African, Caribbean or Black british and 4% were white.
The Government said the large increase in asylum seeking children reflects the increase in the number of asylum seekers arriving on small boats on the south coast.
Overall, 9,226 children were being looked after in Lincolnshire at the end of March in the area with 519 placed in foster care.
Marieke Widmann, Children’s Society policy and practice advisor said: “Children arrive here alone, after a traumatic and dangerous journey, separated from their families and loved ones – some may even have been trafficked to the UK – it’s absolutely essential that they get the right support and protection in place and quickly."
Ms Widmann said these children need clothes, accommodation and help from social workers, but added local authorities are "already stretched to capacity" and struggle to find placements for all children in care.
“There has been a big jump in the number of children put in unregulated placements, up by 23%, and without the right safeguards, these young people are at a massive disadvantage and risk of going missing, being sexually exploited, groomed or coerced into criminal activity like county lines. "
She added it is crucial that the Government provides local authorities with the funding and resources necessary to care for children.
A Department for Education spokesperson said: “Every child deserves a safe and secure home, no matter their background, and local authorities have a responsibility to provide appropriate care for all children in their care."
They added the department recognises the number of children in care has increased and is focused on creating stable homes for them by “removing barriers and reducing delays in adoption”.
“We are also investing millions to create high-quality, safe homes for some of the most vulnerable children or to refurbish existing homes, ahead of a bold reform plan to fundamentally improve children’s social care,” they added.