We live in a country in which, nowadays, one person can move quite readily from one city to another, from one State to another, and pretty much be able to freely get to where they want to go, only needing to have a vehicle, or have the capacity to pay for a bus or train ticket. However, there was a time, way before our interstate system of roads that interconnects all of the States together and thereby made vehicle transportation smooth and safe, in which, people, in order to get from the South to the North, had to walk it, or use river transportation, or a train, and in the era after the Civil War, for Blacks to simply get on a train and travel north was never that easy.
When the civil war ended, the vast majority of Blacks lived in the South, suffering through a situation in which though Constitution Amendments made them equal in the law's eyes, the actual law as applied to Blacks was segregated, discriminatory, restrictive, and wrong. A Black man living in the South was most definitely employable, but only at the jobs that the white man wanted the Black man to work at, and only at pay rates and working conditions that satisfied those white men, so that, Blacks worked, but they worked in the same industry, doing the same sort of things, that they did before their emancipation, which was essentially farming land and being a servant, and any other employment besides those basic jobs, were not readily available for Blacks, and/or subject to an annual tax for such employment, of which the purpose of that tax was to preclude such employment. Additionally, Blacks were often not able to freely travel, without expressed permission, and were subject to severe penalties for vagrancy, so that Blacks that could not prove that they were gainfully employed were effectively forced into plantation labor. In all of these things, Blacks suffered through a system that was a lot like slavery, though not known by that name.
The migratory changes after the Civil war, and up until 1910, demonstrated that Blacks had not moved, for as reported by priceeconomics.com, " In 1910, 89% of African Americans lived in the South," but due to a confluence of many important factors that came together in a very short time, such as an economic depression in cotton prices, along with Northern industries going through a corresponding economic boom in which because of tensions in Europe and ultimately World War I, white immigration from Europe became limited, in addition to America's eventual entry into World War I, taking nearly five million men out of the private sector and being placed into the military, and finally with the labor unrest coming from the newfound power of labor unions, recruiters came down to the South to find, recruit, and take back to the Northern industrial States, able body Blacks at unprecedented rates, which became the very first wave of the Black great migration.
Were it not for Northern States deliberately "importing" Blacks from the south, and thereby, providing the foundation for more Blacks to follow suit as the years rolled by, in which the living and working conditions and pay in the North was fundamentally better, than the stifling suffering left back in the South; though it must be stated, laws, rules, justice, and fairness, were still prejudicial and discriminatory against Blacks in the North, then we would not have seen the real start of Blacks truly becoming someone and something within America, proper, which led to the development of what would be, for the first time ever, the Black middle class.