The “graveyard shift” is a late-night/early-morning work shift.
This work shift was so-named not because it has anything to do with graveyards, but because of the lonesome, spooky feeling of working in the dark silence of the midnight hours and early morning hours when most people are home asleep.
The similar phrase “graveyard watch” originated at about the same time, in the late 1800s, and refers to a shipboard watch from midnight to 4 AM. Sailors aboard ship were in no position to be overseeing graveyards.
The link was explained in this definition, from the American mariner Gershom Bradford, in A Glossary of Sea Terms, 1927: “Graveyard watch, the middle watch or 12 to 4 a.m., because of the number of disasters that occur at this time.” Another source attributes the term to the silence throughout the ship.
Michigan’s The Marshall Expounder, in August 1906, published a piece entitled “Ghosts in Deep Mines,” which said, “And of all superstitions, there are none more weird than those of the ‘graveyard’ shift…usually between 11 p.m. and 3 a.m.”
Many years ago, I worked the graveyard shift as a ‘gofer’ in a rural hospital but never found it spooky. There were always other people moving around. And, if I was lucky, none of the patients moaned.