Segregation in the United States began well before the Civil War and intensified after it, becoming codified in law and practice over the late 19th and early 20th centuries. Here’s a concise outline of when and how it started, with key milestones you can use as a starting point for deeper study. Core timeline

• Colonial era to antebellum period (1600s–1860s): Segregation existed in practice in many colonies and states, often informal or de facto, tied to slavery and racial hierarchy. Enslaved people were controlled through laws and social norms that separated Black communities from White communities.
• Reconstruction and its reversal (1865–1877; 1877 onward): After the Civil War, Black Americans gained civil rights protections briefly, but Southern states quickly moved to reassert racial control through Black Codes and the formalization of segregation.
• Jim Crow era (late 1890s–1960s): Segregation was enshrined in state and local laws across the South and in some border states. The 1896 Supreme Court ruling in Plessy v. Ferguson upheld the “separate but equal” doctrine, legitimizing pervasive public segregation in schools, transportation, restrooms, and other facilities.
• Civil rights movement and dismantling (1950s–1960s): Civil rights activism challenged segregation, culminating in federal legislation like the Civil Rights Act of 1964 and the Voting Rights Act of 1965, which outlawed many forms of discriminatory public segregation and voting barriers.

Key elements to understand

• De facto vs. de jure: Segregation began as informal social separation in many places (de facto) but was increasingly codified into law (de jure) in the late 19th and early 20th centuries.
• Public facilities and education: Public spaces, schools, transportation, and facilities were commonly segregated under the Jim Crow regime, with “separate but equal” rhetoric used to justify unequal access.
• Legal milestones: Plessy v. Ferguson (1896) legitimized segregation under a constitutional doctrine for decades, until subsequent civil rights decisions and legislation overturned many discriminatory practices.

If you’d like, I can pull more precise dates and landmark laws or court cases (like Plessy v. Ferguson, Brown v. Board of Education, Civil Rights Act of 1964) with brief explanations of their impact, or tailor the timeline to a specific region (e.g., the Deep South vs. border states).