In the 1850s, Eli Thayer's New England Emigrant Aid Company promoted free-state emigration to Kansas as a gradualist solution to the slavery problem. In the years after the Civil War, however, Thayer saw his reputation fade in comparison to immediate abolitionists. This essay explores Thayer's attempts to cement his legacy as a true antislavery visionary through continued colonization of Western land and archive building. In uniting the moral superiority of antislavery rhetoric with the jingoism of manifest destiny, Thayer sought to project northern memory of the war beyond issues of citizenship and reconciliation. He both won and lost the battle over the memory of Kansas—his legacy lives on in the archival, imperial narrative he created, but his name remains largely forgotten in the narrative of the Civil War.