Why did Black Americans leave the South after the Civil War and Reconstruction?

The primary factors for migration among southern African Americans were, segregation, indentured servitude, convict leasing, an increase in the spread of racist ideology, widespread lynching (nearly 3,500 African Americans were lynched between 1882 and 1968), and lack of social and economic opportunities in the South.

Explanation:

In the South, Black Americans were often mistreated and discriminated against due to their race. Therefore, a great amount of these Americans moved towards the Northern region where they were treated fairly.

small european communities with shared traditions consolidated into large new states (apex)

the  seven  days  battles  were  a series of seven battles over seven  days from june 25 to july 1, 1862, near richmond, virginia,  during  the american civil war. the  seven  days ended with mcclellan's army in relative safety next to the james river, having suffered almost 16,000 casualtiesduring  the retreat.