Homelessness is the condition and social category of people who lack housing, because they cannot afford (pay for), or are otherwise unable (or uninterested) to maintain, regular, safe, and adequate shelter.

The term homelessness may also include people whose primary nighttime residence is in a homeless shelter, in an institution that provides a temporary residence for individuals intended to be institutionalized, or in a public or private place not designed for use as a regular sleeping accommodation for human beings.

An estimated 100 million people worldwide are homeless.

The United States Department of Housing and Urban Development (HUD) defines a "chronically homeless" person as "an unaccompanied homeless individual with a disabling condition who has either been continuously homeless for a year or more, or has had at least four episodes of homelessness in the past three years."

History of homelessness

Early history through the 1800s

Following the Peasants' Revolt, British constables were authorised under a 1383 statute to collar vagabonds and force them to show their means of support; if they could not, the penalty was gaol. Under a 1495 statute, vagabonds could be sentenced to the stocks for three days and nights; in 1530, whipping was added. The assumption was that vagabonds were unlicensed beggars. In 1547, a bill was passed that subjected vagrants to some of the more extreme provisions of the criminal law, namely two years servitude and branding with a "V" as the penalty for the first offense and death for the second. one arriving in the American colonies in the 18th century were transported convicts. Large numbers of vagabonds were transported along with ordinary criminals.

In the 16th century in England, the state first tried to give housing to vagrants instead of punishing them, by introducing bridewells to take vagrants and train them for a profession. In the 17th and 18th centuries, these were replaced by workhouses but these were intended to discourage too much reliance on state help.

In 1848 Lord Ashley referred to more than 30,000 'naked, filthy, roaming lawless and deserted children', in and around London. By 1922 there were at least 7 million homeless children in Russia as a result of nearly a decade of devastation from World War I and the Russian Civil War.

Although not specifically about the homeless, Jacob Riis wrote about, documented, and photographed the poor and destitute in New York City tenements in the late 1800s. He also wrote a ground-breaking book including such material in How the Other Half Lives in 1890.