A rescue group or rescue organization is dedicated to pet adoption. These groups take unwanted, abandoned, abused, or stray pets and attempt to find suitable new homes for them. Many rescue groups are created by and run by volunteers, who take the animals into their homes and care for them—including training, playing, handling medical issues, and solving behavior problems—until a suitable permanent home can be found.

The first SPCA in the USA was the American Society for the Prevention of Cruelty to Animals (ASPCA), founded by Henry Bergh in New York in 1866. Two years later, the Massachusetts Society for the Prevention of Cruelty to Animals was founded in Boston by a group that included George Thorndike Angell, John Quincy Adams II, Ralph Waldo Emerson, Henry Saltonstall, and William Gordon Weld.[1][6] Examples of other national, nonsheltering humane animal societies include: The Humane Society of the United States, American Humane which was founded in 1877 as a network of local organizations to prevent cruelty to children and animals. The sheltering humane societies include: Peninsula Humane Society and The Humane Society of Allen County. Many local humane societies were founded earlier, and are independent of these similarly named organizations, therefore, local humane groups called SPCA or Humane Society are not related to the national groups such as the Humane Society of the United States or the ASPCA.