Mark Schatz was working as superintendent of Glen Haven Memorial Park 49 years ago when he got the idea to open his own grave-marking business.

"I saw a need for it," he said.

There was a market for a grave-marker company in the area, and something about the business always appealed to him, Mr. Schatz said.

"A person deserves to have their grave marked," he said. "I've never liked the idea of people spending eternity in an unmarked grave."

After nearly half a century of operating Maryland Memorials with his wife, Ann, the couple retired from the business on Crain Highway earlier this year. The company remains open...