The Politics of Andrew Johnson
- Examines the bitter political battle that caused the only impeachment of an American President.
- http://historymatters.gmu.edu/impeach2.html

American Presidents: Andrew Johnson
- A collection of facts and trivia about Johnson's life.
- http://www.americanpresidents.org/presidents/president.asp?PresidentNumber=17

Impeachment Trial of President Andrew Johnson
- Short biography of U.S. Supreme Court Justice Salmon Portland Chase tells how he stood against an angry U.S. Senate mob during the impeachment proceedings.
- http://odur.let.rug.nl/~usa/B/spchase/chase05.htm

The Impeachment Trial of Andrew Johnson
- Provides a detailed account of the trial and explores the issues that surrounded it.
- http://www.law.umkc.edu/faculty/projects/ftrials/impeach/impeachmt.htm

The Impeachment of Andrew Johnson
- Features more than 200 excerpts about the historic proceedings from Harper's Weekly, the leading weekly newspaper of the era.
- http://www.impeach-andrewjohnson.com/