In the Windy City. Chicago had 109,260 residents in 1860, and prided itself on being the center of the Western states and territories. As a gesture, or nod, to the growing importance of the West, the Republicans held the convention—only the second in their history—in Chicago.

To play up the Western and frontier themes, the Republican Party organizers had an enormous, temporary building constructed; labeled the Wigwam, this tentlike structure was well remembered for many years. The two major candidates were William H. Seward of New York and Abraham Lincoln of Illinois, and as the convention began, on May 15, 1860, most well-regarded observers thought that Seward had the edge. He was still better known than Lincoln, and thanks to his outspokenness on the issue of slavery, he was more acceptable to the radical, or extreme abolitionist, wing of the Republican Party. As so often, the political men underestimated Lincoln and his political team.