What factors encouraged american economic growth in the decades after the civil war?

The Civil War ended with a victory for the North.  It used its superior resources to defeat the South.  Sherman’s campaign in the South destroyed everything that could have helped the Confederate cause while Grant held Lee at Petersburg until Lee had no choice but to surrender.  The war resolved the social issue of slavery.  Lincoln had already issued the Proclamation of Emancipation which freed all slaves both in the North as well as the South.  It abolished the system of slavery for African Americans who fought for the Union.  It also preserved the Union and made America one nation.

What area are in blue