Nicka Sewell-Smith spent 20 years searching for her family’s origin. After beginning research on her roots, she discovered that the first generation of college graduates in her family were grandchildren of former slaves.

“When you know your family’s history you’re able to connect back to those seminal events in a different way,” she says. “You actually have a name and information that you can call out that will tie you directly back to those names.”

Because enslaved people didn’t have legal rights prior to 1865, it can be difficult to track them through censuses or birth, marriage and death records. Much of what Sewell-Smith, a professional genealogist, knows about her ancestors comes from oral history, documents and photos that were left behind by grandparents.

In 2017, Sewell-Smith became a consultant with Ancestry.com, which last month released the world’s largest digitized collection of the Freedmen’s Bank and Freedmen’s Bureau, a federal agency created for formerly enslaved people near the end of the Civil War. The agency helped them get food and clothing but also education and legal marriage status in the country.

“It just covered so many aspects of American life. You know, from schools to rations and clothing, it’s an incredible way to learn about what was going on in our country as it tried to stabilize itself after the Civil War,” says Sewell-Smith, who spent 14 years going through the collection image by image.

The Freedmen’s Bureau remained in operation until 1872, which meant that millions of pages of records…