Black history in the U.S. Congress is a rich and complex story that has evolved over centuries. Some key milestones include:

- The first Black Americans to serve in Congress were Hiram Rhodes Revels and Joseph Rainey, who were elected to the Senate and House of Representatives, respectively, during the Reconstruction era following the Civil War. Revels was the first African American to serve in the U.S. Senate, representing Mississippi from 1870-1871, while Rainey was the first African American to serve in the U.S. House of Representatives, representing South Carolina from 1870-1879.

- The era of Reconstruction saw a number of Black Americans elected to Congress, but these gains were short-lived as Reconstruction ended and Southern states implemented Jim Crow laws and other measures to suppress Black voter turnout and political power.

- It wasn't until the mid-20th century, during the Civil Rights Movement, that significant numbers of Black Americans were elected to Congress again. Notable figures from this era include Barbara Jordan, who was the first African American woman elected to Congress from the South in 1972, and Shirley Chisholm, who was the first Black woman to seek the presidential nomination of a major party in 1972.

- In recent years, the number of Black Americans serving in Congress has steadily increased, with figures like John Lewis, Maxine Waters, and Cory Booker making significant impacts on national politics.

Overall, the history of Black Americans in Congress reflects the broader struggle for political equality and representation in the United States, and these trailblazing individuals have played a crucial role in shaping the nation's laws and policies.