I currently volunteer at an Animal Shelter during my free time.
Well thank you for doing that.  It's kind of nice how people have changed the name pound, to animal shelter, to change the thought process associated with the word.
Yes it definitely sounds better!
I believe the phrase was coined when animals or stray livestock would have to be penned or "impounded" until claimed by whoever owned them.
That makes sense. When did animal shelters come to exist?
Humane Society of the United States
The Humane Society of the United States (HSUS), based in Washington, D.C., is an American nonprofit organization founded by journalist Fred Myers and Helen Jones, Larry Andrews, and Marcia Glaser in 1954, to address what they saw as animal-related cruelties of national scope, and to resolve animal welfare problems by applying strategies beyond the resources or abilities of local organizations. In 2013, the "Chronicle of Philanthropy" identified HSUS as the 136th largest charity in the United States in
Humane Society of Pinellas
The Humane Society of Pinellas is an animal shelter located in Clearwater, FL which houses nearly 400 animals at any given time.
History.
The Humane Society of Pinellas was founded in 1956, then known as the Society for the Prevention of Cruelty to Animals of Clearwater or SPCA Clearwater. In 1988, after the founding of another local animal shelter, the SPCA Clearwater changed its name to the Humane Society of North Pinellas. The shelter underwent another name change, and in 2000, officially became