Forney, from Walkersville, Maryland, was found by a fellow Midshipman. He was transported to Anne Arundel Medical Center, where he was pronounced dead at 11:28 p.m. ET. He was 22.
A cause of death hasn't been announced.
"Words cannot express our pain and sorrow," Navy coach Ken Niumatalolo said in a statement. "First and foremost, our deepest condolences to the Forney family. The Navy football brotherhood is not a team, we are a family. We are devastated to have lost one of our brothers. We all loved -- and will always love -- David. We pray for strength during this most difficult time."
Forney, who played at Georgetown Prep in Washington, D.C., was a three-year letterman and played in 39 straight games during his final three seasons at Navy. As a senior in 2019, he started all 13 games at left guard and was named All-AAC.
Navy led the FBS in rushing with 360.5 yards per game.
"The entire Naval Academy family -- the Brigade of Midshipmen, the faculty, staff and coaches -- are heartbroken over the tragic and unexpected loss of Midshipman David Forney," said Vice Adm. Sean Buck, superintendent of the Naval Academy. "On behalf of the Naval Academy family, my wife, Joanne, and I extend our deepest condolences and heartfelt sympathies to the Forney family, their friends, as well as to David's extended Naval Academy family."
Forney would have graduated on May 22 and been commissioned as a cryptologic warfare officer.