Liz Nelson

The Desert Sun

Corwin has been missing since June 28

The search encompasses more than 200 square miles

Corwin recently learned she was pregnant

Police%3A Disappearance %27not voluntary%27

Published July 15, 2014.

Erin Corwin is 20 years old today.

Corwin has been missing from her home at the Marine Corps Air Ground Combat Center at Twentynine Palms since June 28. So far, a massive search covering at least 200 square miles of treacherous high desert terrain has turned up no clues about where she went and why she hasn't been in touch.

Corwin's husband, Lance Cpl. Jonathan Corwin, reported her missing on June 29, 24 hours after he says he last saw her leave the couple's house, get in her car and drive in the direction of Joshua Tree National Park. She was heading to the desert preserve, said her husband, to scout locations for picture-taking during an upcoming visit from her mom. According to police, Corwin's disappearance is "not voluntary."

On Facebook, the Locate Erin page has amassed more than 17,000 followers since her disappearance with concern and support for her family coming from as far away as Thailand and Australia.

A message posted this morning to mark Erin's birthday has already drawn close to 100 comments and more continue to pour in.

"I don't know her personally but have been praying for her, her husband and her family everyday," writes one commenter. "Let today be the day that she is found safe and sound and returned to her loved ones. Prayers from GA."

"HBD, Beautiful ♡," writes another. "Praying you are found unharmed and returned to your family."

On Monday evening, Marines and their families gathered at Twentynine Palms to share their grief -- and fears -- about the missing friend and neighbor.

Anyone with information about Erin Corwin is urged to contact the San Bernardino County Sheriff's Specialized Investigation Division at (909) 387-3589 or sheriff's dispatch at (909)387-8313. Anonymous tips can be called in to the WeTip Hotline at (800) 78-CRIME (27463) or at www.wetip.com

Corwin is described as white, 5-foot-2, weighing 120 pounds with brown hair and blue eyes.