The extensive collection of Hannah Arendt’s papers held at the Library of Congress are available online.
The papers of author, educator, political philosopher, and public intellectual Hannah Arendt (1906-1975) constitute a large and diverse collection (25,000 items; 82,597 images) reflecting a complex career. The collection spans the years 1898 to 1977, with the bulk of the material beginning in 1948, three years before Arendt’s naturalization as an American citizen. The papers contain correspondence, articles, lectures, speeches, book manuscripts, transcripts of Adolf Eichmann’s trial proceedings, notes, printed matter pertaining to Arendt’s writings, family and personal materials, evidence of Arendt’s network of fellow intellectuals, editors, writers, and theorists, and documentation of her academic affiliations and courses taught.
Arendt biographer Samantha Rose Hill has a good piece at Literary Hub on the archives and her own work with them.