Positive outcomes of the Civil War included a stronger United States government and the abolition of slavery, while negative outcomes included a high death toll and ongoing racial strife. The Civil War took place from 1861-1865 and literally divided America.
Perhaps the most positive result of the Civil War was that it brought an end to slavery. The Emancipation Proclamation, which President Lincoln presented midway through the war, freed slaves in the seceded Southern States. The 13th Amendment, outlawing slavery completely, was adopted in 1865, 8 months after the Civil War ended. America's abolition of slavery helped to further international antislavery efforts as well.
The Union's victory led to a stronger United States government. The Confederate secession had challenged the federal government's authority. However, by defeating the Confederates and preserving the Union, America's federal government was able to present a strong front to the world and became a major force in international relations, as it did, for example, during its intervention in the Mexican civil war.
There were, however, negative effects, too. Over 600,000 people died in the war, making it America's bloodiest war and leaving untold numbers of widows and children to fend for themselves. The Civil War had lasting impacts on the economy, politics, infrastructure and social fabric of the American south. The south had come to rely on slavery as the basis of its economy, and following the war, it had to rebuild from scratch. Racial tensions resulting from sudden, forced abolition led to decades of strife. The Jim Crow laws, for example, can be seen as a consequence of the Civil War.