One in 30 American children are homeless, according to a new state-by-state report that finds racial disparities, increasing poverty and domestic violence responsible for the historic high.

According to the report released on Monday by the National Center on Family Homelessness, child homelessness increased in 31 states and the District of Columbia. Nearly 2.5 million children experienced homelessness in the US in 2013, an 8% rise nationally from 2012.

California and states in the south and south-west ranked particularly poorly in an analysis of homelessness, state responses and associated factors. According to the report, California has more than 500,000 homeless children, a high cost of living and only 11,316 housing units for homeless families; only Alabama and Mississippi, with chronically bad poverty rates, ranked worse.

“Child homelessness has reached epidemic proportions in America,” Dr Carmela DeCandia, director of the center, said in a release with the report. “Living in shelters, neighbors’ basements, cars, campgrounds and worse – homeless children are the most invisible and neglected individuals in our society.”

Factors that cause the high rates of child homelessness included high rates of family poverty, particularly in houses headed by single women who are black or Hispanic; a dearth of affordable housing for low-income families; fallout from the recession economy, such as foreclosures and debt; long-lasting effects of trauma; and institutional racism resulting in economic segregation. The report cites a 1999 finding that black children under five were 29 times more likely than white children to be in an emergency shelter.

The report makes special note of the potentially devastating long-term effects of poverty and homelessness on children, showing research that indicates “up to 25% of homeless pre-school children have mental health problems … this increases to 40% among homeless school-age children.” The compilation of Department of Education data, medical and societal research finds that homeless children are more likely to get sick, miss school and have cognitive and emotional problems.

North-east and midwest states and Hawaii rank among those best prepared to prevent child homelessness. Minnesota, Nebraska and Massachusetts, rated best, each have relatively low levels of poverty and effective state policies.

The National Center on Family Homelessness, part of a larger, private non-profit, the American Institutes for Research, endorses new plans to support mothers, increase affordable housing and treat and prevent trauma-related disorders.

The definition of homelessness is part of the government’s problem in approaching the issue. In a one-day tally performed in January 2013, the Department of Housing and Urban Development (HUD) counted 610,042 homeless people in the US, including 130,515 children. The estimate is vastly lower than Department of Education data, which includes homeless families staying in motels or with friends or family.

Non-profit First Focus Campaign for Children has introduced a bill in Congress to expand HUD’s definition, but it does not propose new spending for homeless children.