There are four types of homelessness:
Chronic homelessness
The most common type, where someone is homeless for over a year

Episodic homelessness
Where someone experiences three episodes of homelessness within a year

Transitional homelessness
A popular misconception is that homelessness is a chronic condition

Hidden homelessness
A type of homelessness that presents its own set of challenges such as living in cars

The top causes of homelessness among families are:
Lack of affordable housing
Unemployment
Poverty
Low wages
Other factors that contribute to homelessness include:
Income and housing affordability
Escaping violence
Impact of racial disparities

The US Department of Housing and Urban Development (HUD) defines homelessness as individuals or families who lack a fixed, regular, and adequate nighttime residence. This includes people who are living in a place not meant for human habitation, such as a public or private place, or in a shelter.

HUD also considers people homeless if they are losing their primary nighttime residence within 14 days and lack resources or support networks to remain in housing. This includes people who are staying with friends, but cannot stay there for longer than 14 days.

HUD has four categories of homelessness:
Literally homeless
Imminent risk of homelessness
Homeless under other federal statutes
Fleeing/attempting to flee domestic violence