There were many reasons why the North of America decided to abolish slavery. There were many varying opinions and it became a complex issue within society. The North was less suited to plantations, and therefore benefitted less to slavery. The North was primarily industrial, with very limited need for slave labour. On top of this, the North developed more new technologies and resources that made labour work easier, and in some cases replaced the need for labourers. This further reduced the need and reliance on slaves.
Without this agricultural, and therefore economical, reliance on slaves, the people of the North would be more open to ending slavery. The North wanted to stop slavery in order to reduce the economic power slavery gave to the South. The south relied heavily on slavery in order to sustain the large number of plantations, specifically rice, cotton and sugar. The plantations in the South were hugely successful, and sold large quantities of produce. The plantations relied on the slaves for free labour and skill, and in turn the South relied upon the plantations for the wealth they brought.
With the North becoming increasing industrial, the ideologies of the North were changing and developing as well. Many people now considered slavery unconstitutional, believing that African Americans deserved rights and freedoms along with the rest of society. Many famous politicians were pro-abolition, as were other high profile people throughout the North. Abolition became a high profile issue, and often appeared in newspapers, and popular literature and books.