Lorna Gail Woods had heard stories of the Clotilda since before she could speak. In the evenings, her grandmother would hold her on the porch and tell her the tale of how her great-great-grandfather came to Alabama on the last known slave ship to come to the United States.

They were brought by force, her grandmother would tell her, by an American businessman who just wanted to win a bet. Her great-great-grandfather Charlie Lewis was the oldest of 110 slaves bought in West Africa, chained in the hull of the Clotilda and sailed across the Atlantic to the Mobile-Tensaw River Delta in Alabama in 1860. But after the slaves were unloaded, the crew burned the ship, and its wreckage was never found, so many people doubted the story.

“My grandmother would tell us the story so we wouldn’t forget and so that we could continue to tell the story,” Ms. Woods, 69, said over the phone in a warm, Southern cadence.

On Monday, the story that Ms. Woods’s family — and many like hers in Africatown, the historic neighborhood of about 2,000 on the shores of the delta just north of Mobile — had passed down for more than 150 years became much more real.