Academic standards for history in all states require students to learn about deeply troubling events, such as war, genocide, and slavery. Drawing on research and theories related to trauma studies and history education, this ethnographic study aims to better understand what happens when teachers and students examine the pain and suffering of others in the shared social place of an urban U.S. history classroom. In order to clarify how such troubling events are co-constructed and experienced in the classroom, I first outline a framework for conceptualizing difficult histories as histories where three interrelated components are present: (a) content centered on traumatic events; (b) a sense of identification between those studying the history and those represented in history; and (c) a moral response to these events. Analysis revealed that only two of the histories addressed over the course of one semester were co-constructed by the teacher and her students as difficult histories: slavery and Westward Expansion. Yet, even though slavery and Westward Expansion shared the defining characteristics of difficult histories, there were significant differences in how difficulty was constructed in the classroom. Analysis also revealed that the diverse group of students in this study used their understandings of these difficult histories to engage in similar activities, such as finding evidence of how they belong in America, making sense of America, and morally responding to past and present events. In both slavery and Westward Expansion, students relied heavily on their own personal experiences and beliefs to make sense of these histories. Throughout this research, the power of personal beliefs and experiences, especially those related to issues of race and ethnicity, remained crucial to students' historical understanding. They were central to students' participation in co-constructing slavery and Westward Expansion as difficult histories in the classroom and in their own applications of historical knowledge. At times these personal beliefs were vehicles to better understand distant others and at other times, they were barriers. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]