Programs authorized under federal or state legislation or local government initiatives that provide financial assistance and supportive services for individuals and/or families who are homeless or at risk for homelessness. Included are prevention programs that help people at imminent risk for homelessness preserve current housing or secure alternative housing; diversion programs that help people actively seeking shelter to identify and access viable alternatives including shared housing arrangements and transitional housing/shelter; and rapid re-housing programs that help people who are already homeless move as quickly as possible into permanent housing. Services may include case management, rental deposits, rent assistance, utility deposits, housing search assistance, moving expenses, expenses related to non-shelter temporary housing in situations where permanent housing has been secured but is currently unavailable, and other costs the family may incur in the process of acquiring or maintaining housing. Allowable activities, eligibility criteria and other requirements vary depending on the jurisdiction, the funding source and the focus of the program.

Individuals or families who are at risk for becoming homeless because they are unable to make their rent or mortgage payment and face eviction or foreclosure or who have already lost their permanent residence and are "doubled up", i.e., are staying temporarily with friends or relatives.

Individuals and families who have no fixed, regular and adequate residence, who are residing temporarily with relatives or friends or who live on the street, in emergency or transitional shelters, in a hotel or motel paid for with a shelter voucher, in seriously substandard housing or in an abandoned building, place of business, car or other vehicle, or other public or private place that is not ordinarily used as a regular sleeping accommodation for people. Some people who are homeless have issues with substance abuse, chronic or severe mental illness, chronic unemployment or underemployment, or other problems that prevent them from obtaining housing.

Families, usually consisting of two parents and their children but also including single parent families, extended families and nontraditional family groups, who have no fixed, regular and adequate residence, who are residing temporarily with relatives or friends or who live on the street, in emergency or transitional shelters, in a hotel or motel paid for with a shelter voucher, in seriously substandard housing or in an abandoned building, place of business, car or other vehicle, or other public or private place that is not ordinarily used as a regular sleeping accommodation for people.

Children or adolescents who have been abandoned by the adults responsible for their care or who have left their homes without notice or parental consent and who have no fixed place of residence.