There was much less formal segregation in the North than there was in the South. The most prevalent type of segregation in the North was school segregation. For example, laws in the state of Indiana allowed local school districts to engage in segregation until 1948. In many other states, communities nearer to the South practiced segregation even though it was illegal.
Most of the segregation in the North, however, was less formal. It took the form of residential segregation, with white people refusing to sell homes to black people. Sometimes, there were even restrictive covenants, which were contracts that you signed when you bought a house, promising never to sell to a non-white. This sort of segregation was what Martin Luther King, Jr. was protesting in the suburbs of Chicago when he was hit in the head with a brick.