• Homelessness is defined as the condition in which (i) an individual or family lacks a fixed, regular, and adequate nighttime residence; or (ii) an individual or family who has a primary nighttime residence that is (a) a public or private place not meant for human habitation, (b) living in a publicly or privately operated shelter designated to provide temporary living arrangements, or (c) exiting an institution where they have resided for 90 days or less and who resided in an emergency shelter or place not meant for human habitation immediately before entering that institution (1).
  • Chronic homelessness is defined as an individual who has experienced homelessness for at least 1 year, or experienced homelessness at least 4 times in the past 3 years. These people typically have complex and chronic medical illnesses such as mental illness, substance use disorders, physical disabilities, and other medical conditions that further hinder their ability to obtain or maintain housing (1).


In 2020, homelessness increased by 2%, marking the 4th year in a row of nation-level increases. However, when compared with 2007, homelessness is down by 12% (1).

As of January 2019, 0.17% of the total United States population, or approximately 580,466 individuals, experienced homelessness on any given night: 63% in sheltered locations such as emergency shelters or transitional housing and 37% in unsheltered locations such as on the street, in abandoned buildings, or any place unfit for human habitation. The 2020 Annual Homeless Assessment Report examines trends within subpopulations of the homeless.

  • Around 40,000 (7%) of homeless individuals are veterans. This group has experienced the greatest decrease in homelessness over the last decade as a result of prioritized policy making.
  • 96,000 (17%) are chronically homeless.
  • 34,000 (6%) are unaccompanied youth.
  • 226,000 (40%) are African Americans, a group disproportionately affected because they make up 13% of the U.S. population.
  • The COVID-19 crisis is expected to exacerbate homelessness across the board; however, data is not available at time of update. For 2021, COVID-19–related health concerns disrupted counts of unsheltered people.

Risk Factors

  • Economic factors
    • Poverty
      • 2021 Federal poverty definition: $26,500 annual income for four-person household in the lower 48 states and District of Columbia, slightly higher in Alaska and Hawaii
      • In 2020, 11.4% of the U.S. population fell below federal poverty definition (U.S. Census Bureau); this represents a 1% increase from 2019.
    • Unemployment: U.S. rate 4.8% in September 2021 (U.S. Bureau of Labor Statistics)
    • Lack of affordable health care: In 2020, 9.7% of people in the United States (31.6 million) were uninsured for the entire calendar year.
      • Working age adults (ages 19 to 64 years) had a lower rate of health insurance when compared to children and older adults. Those aged 26 to 34 years were least likely to be insured. The uninsured rate for ages 19 to 25 years decreased by 12% between 2009 and 2016, following The Affordable Care Act provision allowing individuals in this age group to stay on parental insurance plans.
    • Lack of affordable housing. Affordable housing is defined as housing in which the occupant(s) is paying no more than 30% of gross income for housing costs, including utilities. An estimated 37.8 million U.S. households face cost burdens in housing (>30% of income is spent on housing) and 18.2 million households are “severely housing cost burdened” (≥50% of income is spent on housing).
  • Additional at-risk populations: intimate partner violence (IPV), victims of violence; youth (particularly those aging out of foster care); veterans; rural; addiction; psychiatric illness; disabled due to chronic medical disease, psychiatric illness, or substance use disorder; reentry after incarceration/prison
    • IPV: 12% of overall persons experiencing homelessness, and as many as 1 in 5 families experiencing homelessness will have reported experiencing IPV; IPV leads directly to homelessness in many cases (1).
    • Youth: On a single night in 2019, approximately 35,000 unaccompanied youth <25 years of age experienced homelessness. This is a 4% decrease since the 2018 data collection. 89% were ages 18 to 24 years. 51% of homeless unaccompanied youth were unsheltered.
    • Veterans: The number of homeless veterans decreased by 2% from 2018 to 2019 and by 50% since 2009.
    • Transgender individuals: In 2019, 0.6% of all persons experiencing homelessness identified as transgender and 0.2% identified as gender nonconforming.
    • Addiction disorders: 46% of homeless individuals report alcohol and/or drug use as a major factor contributing to homelessness (1).
    • Psychiatric illness: 25% of adults experiencing homelessness suffer from chronic mental illness (1).
    • Reentry after incarceration: Up to 50,000 people each year enter homeless shelters from jails or prisons (1).
  • Fundamental issues in homelessness and health care that require ongoing consideration:
    • Unstable housing, limited access to nutritious food and water, lack of transportation
    • Higher risk for abuse and violence
    • Physical/cognitive impairments, behavioral health problems
    • Developmental discrepancies for children: speech delay, chronic ear infection, insufficient opportunity to practice gross and fine motor skills
    • Higher risk for communicable disease
    • Lack of health insurance/resources, discontinuous/inaccessible health care, lack of a medical home, barriers to disability assistance
    • Cultural/linguistic barriers: racial and ethnic groups overrepresented in homeless population
    • Limited education/literacy
    • Lack of social supports: Alienation from family and friends precipitate homelessness.
    • Criminalization of homelessness: frequent arrests for loitering, sleeping in public places

General Prevention

  • Policy and funding for community programs to provide emergency/rapid housing, housing stabilization, and case management services. The CARES ACT of 2020 and the American Rescue Plan Act of 2021 provide funding for permanent housing. Over the past 5 years, the fastest growing forms of assistance include rapid rehousing and “other permanent housing.”
  • Increased Medicaid eligibility, expanded home and community-based services and case management for people experiencing homelessness
  • HUD: increasing permanent supportive housing units, increasing services for veterans, families with children and those with disabilities
  • Social justice policy recommendations: permanent affordable housing, foreclosure and homelessness prevention, increased funds for HUD McKinney-Vento programs (emergency, transitional, and permanent housing) and National Housing Trust Fund, rural homeless assistance, universal health care, universal livable income, employment/workforce services, prevention of hate crimes against the homeless, decriminalization of homelessness

Commonly Associated Conditions

  • Hunger and malnutrition
  • Exposure-related conditions (frostbite, heatstroke)
  • Substance use disorders and their associated conditions
    • Liver disease (alcohol, hepatitis B and C)
    • Abscesses (intravenous drug use)
    • Overdose
  • Dental problems
  • Psychiatric illness
  • Trauma (increased risk of assault, victims of hate crime)
  • Infectious diseases
    • Skin/nail infection and infestation (lice, bedbugs, and scabies)
    • Tuberculosis (TB), HIV/AIDS, STI
  • Worsening of chronic medical conditions: lack of healthy food, places to store medications, or medical equipment; lack of restful sleep; decreased health literacy; limited transportation to appointments

There's more to see -- the rest of this topic is available only to subscribers.