The 13th Amendment to the U.S. Constitution abolished slavery and involuntary servitude, except as punishment for a crime for which one has been convicted. Passed by Congress in 1865 and ratified later that year, the amendment formally ended slavery across the United States. However, it allowed for exceptions in cases of criminal punishment, which some argue led to exploitative convict leasing systems and the modern system of mass incarceration in the U.S. The document provides an overview of primary sources and historical collections at the Library of Congress related to the 13th Amendment and the abolition of slavery.