With 2.3 million people behind bars, the United States imprisons a higher
percentage of its population than any other nation in the world. For a
prisoner, being able to write to someone “on the outside” can make a world
of difference. A letter is often the brightest point of a prisoner's day.
These links may be useful to share with folks you know who would like to begin
corresponding with prisoners:
How to Find a Prison Pen Pal
How to Write a Prisoner