The Georgia poet Sidney Lanier immortalized the seacoast there in his poem, "The Marshes of Glynn", which begins: During World War II, Naval Air Station Glynco, named for the county, was a major base for training for blimps and anti-submarine warfare.

The Federal Law Enforcement Training Center (FLETC) now uses a substantial part of the former NAS as its main campus.

Most of the county's northern and northwestern border area is located in the Altamaha River sub-basin of the basin by the same name.

[22] The Hanlin Group, Inc., which maintained a facility named "LCP Chemicals" in Glynn County just outside the corporate limits of Brunswick, was convicted of dumping 150 tons of mercury into Purvis Creek, a tributary of the Turtle River and surrounding tidal marshes between the mid-1980s and its closure in 1994.

It had been under scrutiny by the EPA after Service biologists discovered mercury poisoning in endangered wood storks on St. Simons Island.

Fish, shellfish, crabs, and shrimps taken in coastal waters, as well as other bird species, also contained the toxic metal.