While the word “diagnosis” can be traced back to the seventeenth century, the verb “to diagnose” does not appear in written works until 1861, when American writers began to contend with new methods of medical examination. Literary texts soon resonated with an underlying fear of “undiagnosable” conditions (1873) and condemned the “evil” of “self-diagnosis” (1883); they began to mimic emergent medical techniques used to define discrete “Names of Sickness,” to use Emily Dickinson’s phrase. This dissertation, "The Names of Sickness: Writing Disability and Revising Diagnosis in Nineteenth-Century America," analyzes texts by women writers from the Civil War through Reconstruction to argue that literature transforms diagnosis from an alienating process of labeling into a tool for social critique. Drawing upon contemporary scholarship in critical feminist and intersectional disability studies, I assert that literature articulates disability even if we cannot—or will not—diagnose authors themselves. The dissertation asks how diagnostic methods can be redirected away from individual bodies and minds and towards systemic issues such as racial prejudice and gender violence—a question that attests to the value of humanistic inquiry during times of political and medical crisis. This first book-length study of disability in American women’s writing is divided into three primary chapters. I first argue that Emily Dickinson defied diagnostic labels while she shaped pain’s expansiveness into poetic form. Chapter Two asserts that Charlotte Perkins Gilman’s story “The Yellow Wallpaper” embraces the chaos created by patriarchal medicine to energize collaborative resistance. Finally, Chapter Three argues that Frances E.W. Harper’s novel Iola Leroy figuratively “diagnoses” systemic conditions, such as the “virus of slavery and injustice.” Significantly, Harper does not advocate for the eradication of disability; instead, she asserts the power of community for disabled and chronically ill women. My project thus emphasizes the transformative power of writing and community as it explores the ways women resist and revise diagnostic methods to challenge ableist violence. Ultimately, I assert that literary inquiry is imperative to grappling with crisis for which there is no immediate cure, and advocate for a humanistic approach to interpreting the names we give to sickness.