33 star flag flown over Fort Sumter - 1861. Each state, southern states included, continued to be represented on the flag for the duration of the conflict. The Union flag underwent several changes throughout the war as states were added. Variations may also be attributed to individual flag makers in each state.
I have always thought that all men should be free; but if any should be slaves, it should be first those who desire it for themselves, and secondly, those who desire it for others. When I hear anyone arguing for slavery, I feel a strong impulse to see it tried on him personally. - Abraham Lincoln, Statement to an Indiana Regiment passing through Washington (17 March 1865)