The Innovator Who Advised a President: John A. Dahlgren! John A. Dahlgren is the most famous Swedish American you may never have heard of.

Born in Philadelphia on November 13, 1809, John A. Dahlgren was the son of Bernhard Ulric Dahlgren, the Swedish Consul General in Philadelphia. John eventually began his career on board the USS Macedonian in 1826.

Eventually the Navy assigned Dahlgren to the U.S. Coast Survey, where he served as a scientist. During this time, Dahlgren studied naval ordnance and was tasked with exploring ways to improve weaponry through emerging technologies and more precise engineering. By 1847, Dahlgren was regarded as an ordinance expert and was assigned to the Bureau of Ordnance and Hydrography at the Washington Navy Yard.

His most famous innovation, the eponymous Dahlgren gun, was a shockingly effective design. It featured increased power, accuracy, and penetrative ability alongside a unique contoured shape, which distributed pressure more evenly and made it safer to fire explosive shells.

When war broke out in 1861 and most officers at the Washington Navy Yard resigned due to Confederate sympathies, Dahlgren was made Commandant by special order of President Abraham Lincoln. In 1863, Dahlgren, now Rear Admiral, was tasked with capturing Charleston and cutting off Confederate supply lines. When Dahlgren failed, Lincoln came under pressure to replace him. Angered, Lincoln replied that he “would be damned if he would do anything to discredit or disgrace John A. Dahlgren.”

In recognition of John A. Dahlgren, ASHM features two great examples of these guns on either side of the Museum’s FDR Park-facing façade. Originally on board the wooden, steam-powered USS Osceola and USS Ticonderoga during the Civil War, these cannons were put into storage in the latter half of the nineteenth century before finally arriving in South Philly in 1938 when ASHM celebrated its grand opening.

We welcome you to tour our museum and learn more about John A. Dahlgren! https://www.americanswedish.org/