Kim posted pics of her visit alongside supermodel sister Kendall Jenner and Influencer Olivia Pierson to Pine Grove Youth Firecamp and Growlersburg Firecamp In Northern California.

Kim captioned the post saying, "Yesterday I had the amazing opportunity to spend some time with the guys at Pine Grove youth firecamp, and Growlersberg Firecamp Crew 3 and 5. These incredible men are incarcerated firefighters saving our state, homes and communities from fire."

She continued ... "This program is the first of its kind allowing 18-25 year old incarcerated people to get out of prisons and into a firecamp to serve the community. Through this voluntary program they can fully expunge their felony records when they are released and now can go into firefighting careers when they get out."

As we've previously reported ... Kim regularly uses her platform to advocate for criminal justice reform -- even meeting with Vice President Kamala Harris back in April for a roundtable discussion after Joe Biden granted clemency to 16 people previously convicted of nonviolent drug offenses.

As you may recall ... Kim faced some heat for meeting with Donald Trump in 2018 after he commuted Alice Marie Johnson's life sentence ... in large part thanks to Kim's advocacy efforts.

Kim has made it clear her only agenda is to advocate for prison reform, no matter who's in office.