More than a dozen homeless children in South Hams were living in temporary accommodation as of June, new figures show.
Meanwhile more than 172,000 children were in this situation across England, a record high.
This Friday marks International Day for the Eradication of Poverty, which this year focuses on "ending social and institutional maltreatment by ensuring respect and effective support for families".
New figures from the Ministry of Housing, Communities and Local Government show 14 children in South Hams were homeless and living in temporary accommodation at the end of June – up from 11 a year earlier.
Across England, 172,420 children were in this situation.
This marked an 8% increase on the previous year and is the highest number since records began.
Overall, there were 132,410 homeless households in temporary accommodation across the country at the end of June, including 84,240 with dependent children.
Of those, 33 households were in South Hams, of which eight with children.
Mairi MacRae, director of campaigns and policy at Shelter, said: "It’s utterly shameful that the number of children homeless could now fill a city the size of Oxford.
"Thousands face a long grim winter stuck in temporary accommodation, including freezing bedsits and cramped B&Bs, because successive governments have passed the buck for a housing emergency of their making.
"Every day we hear from families who are terrified of spending months or even years in appalling conditions, watching their breath hang in the air as damp and mould climbs the walls."
She added: "The Government must unfreeze local housing allowance in the Autumn Budget so that it covers at least the bottom third of local rents, to prevent more families from being caught in the rising tide of homelessness.
"And in the long-term, the Government must set an ambitious national target for the number of social rent homes it wants to see delivered – we need 90,000 a year for 10 years to end homelessness for good."
Latest Office for National Statistics estimates show Oxford’s population is around 165,000.
Dr Lisa Doyle, Centrepoint’s head of policy and public affairs, said: "Experiencing homelessness and housing instability at such a young age can have devastating effects on a child’s mental health and their ability to live independently in the future.
"Things need to change. What’s needed now is decisive action to tackle the housing crisis and a clear plan for reducing and preventing homelessness across the country."
Homelessness Minister Alison McGovern said the figures "are a harsh reminder that too many have been let down by the system meant to protect them".
She added: "We’re seeing signs of progress with the number of households with children in bed and breakfast accommodation continuing to decrease, and the number of households requiring homelessness support falling – but I know that’s not enough to fix years of failure.
"That is why we are digging deep to tackle the root causes, investing £1 billion in 2025-26, including an additional £84 million to prevent homelessness this winter, building 1.5 million homes and £39 billion for the Social and Affordable Homes Programme, scrapping Section 21 evictions, and raising standards to ensure safe and secure housing for all."