Each year, the Transportation Security Administration announces the 10 most unusual items flagged at its security checkpoints. The list for 2026 could include something that turned up at the Gulf Shores International Airport in Alabama: five Civil War-era cannonballs in a passenger’s checked luggage.

Justin Dupree, the lead officer for the T.S.A. at the airport, discovered the relics of Civil War history this month in a routine scan of luggage going under a plane.

Initially, he was concerned.

“My first thought was, ‘I couldn’t see a fuse and need to get some help quick,’” Mr. Dupree said in a release posted on the agency’s website last week. “I couldn’t see the entire item but was scared I might have been holding a live explosive.”

Jesse Fosnaugh, the airport director, said in an interview that the scan revealed five objects with a density that the detector could not see through, and that they were “rusted” and “pitted out.”

Mr. Fosnaugh said two of the objects were the size of grapefruits, and the other three were a little over an inch in size.

Mr. Dupree alerted his supervisor. After the officials determined there was no explosive risk, deputies from the Baldwin County Sheriff’s Office questioned two passengers, a woman and a boy who was traveling with her and had the cannonballs in his bag.

The woman told the police they had bought the cannonballs from a roadside stand, Mr. Fosnaugh said.

The woman and boy surrendered the munitions and then boarded an Allegiant Airlines flight to Oklahoma City. No criminal charges were filed.

“It’s a unique story to tell, and no one got hurt,” Mr. Fosnaugh said.

Police eventually connected the cannonballs to Fort Morgan, a local landmark that is 25 miles west of the airport. Built after the War of 1812, Fort Morgan was used during the American Civil War, the Spanish-American War, World War I and World War II.

Fort Morgan was involved in the Battle of Mobile Bay in 1864 during the Civil War. Following a siege by Union forces that lasted two weeks, Confederate soldiers surrendered.

The cannonballs have been returned to Fort Morgan, according to the T.S.A.

In an email, an Alabama state official that oversees the fort declined to comment because of an open investigation.

In its most recent list of unusual items seized at T.S.A. checkpoints, the agency described a related find at the Boise Airport in Idaho: replicas of pipe bombs and C4 plastic explosive.

“Realistic replicas of explosives are not allowed in checked or carry-on bags,” James Spies, the T.S.A. federal security director for Idaho, said in a 2025 statement from the agency.

After the cannonball find, the T.S.A. advised some packing precautions for passengers.

“Even if inert and not active, travelers should avoid bringing weapons of any kind, including replicas, to the airport,” Tara Corse, the federal security director for Alabama, said on the agency’s website. “They can cause security alerts, flight delays and safety concerns.”