The era in U.S. history defined by massive social, economic, and political change following the Civil War is known as Reconstruction (1865-1877). This period aimed to integrate the Southern states back into the Union and address the status of newly freed African Americans. Key aspects included efforts to establish civil rights, rebuild the South's economy, and implement social reforms. However, Reconstruction faced significant resistance, leading to the rise of discriminatory laws, which ultimately impacted race relations and laid the groundwork for future civil rights struggles.