National Archives recently launched Founders Online (beta), which is a free resource that contains over 119,000 searchable documents, fully annotated, from the authoritative, federally funded Founding Fathers Papers projects. When it is complete it will contain approximately 175,000 documents. Individual editions for George Washington, Benjamin Franklin, John Adams, Thomas Jefferson, Alexander Hamilton, and James Madison. Search by author, recipient or time period.
See the National Archives Press Release from June 13, 2013 for more information.
Painting: John Trumbull