A South Carolina woman has called cops to report her son missing — 20 years after he took off to follow the Grateful Dead.

Margaretta Evans told Myrtle Beach cops that her son Jason Patrick Callahan went on his long, strange trip and that “she has not seen or heard from her son since June of 1995,” according to a police report obtained by The Smoking Gun.

Callahan would be 38 by now. He was described as between 5 feet 10 and 6 feet, 160 pounds with “wavy brown hair and brown eyes,” she’s told police.

Evans “advised that (her son) left to follow the Grateful Dead at that time,” police officer Traci Chanaca wrote.

Cops didn’t immediately say why Evans waited so long to report her son missing.

But this could be connected to a movement by Dead Heads, who have taken to social media recently to try to identify a Dead fan who died in a Virginia car crash on June 26, 1995. The unidentified man was in his early 20s and has been dubbed “Grateful Doe.”