The Tobias Lear papers (140 items) are comprised of 118 letters, one diary, and two engravings. The letters are almost all written by Lear, and relate primarily to his career as the United States Consul General to Tunis and Algiers, and to his contribution to the War of 1812, both as a prisoner negotiator with the British and as a war department secretary. He wrote the bulk of the letters (35) to his wife Frances Dandridge Henley Lear; these contain lengthy discussions of his personal and professional life. Of particular importance is Lear's contemporary account of the illness and death of George Washington.
The first six items relate to Lear's connection with George Washington, including a letter to Washington concerning generals St. Clair and Knox in Philadelphia, and payments for living expenses received by Lear from the United States Treasury. Of note is a record of Lear's eyewitness account of Washington’s death, which provides details on Washington suffering from “the croup,” the doctor's bleeding treatment, and Washington’s last words (between 10 and 11 p.m. on December 14, 1799). Also of note is a letter from Thomas Dobson of Philadelphia concerning the publication of a biography of Washington.
The collection contains one item from Lear's appointment as consul to Saint Domingue, in which he described an uprising against Toussaint L'Ouverture to Secretary of State James Madison (October 27, 1801).
Thirty-nine items relate to Lear's activities as consul general to the Barbary States, including many lengthy letters to his wife describing the negotiations for ransom and Mediterranean trade rights. Lear's negotiations with the Bashaw of Tripoli resulted in the release of some 300 Americans imprisoned as a result of the capture of the frigate Philadelphia . The items dated 1807 give an account of Lear's successful negotiations with the Bey of Tunis.
- July 14, 1803: Copies of letters from James Madison to James Leander Cathcart and Richard O'Brien dealing with affairs between the United States and Barbary potentates: the Bey of Tunis, the Dey of Algiers, and the Pasha of Tripoli
- July 16, 1803 and June 9, 1804: Contemporary copies of letters from Thomas Jefferson to the Dey of Algiers, appointing Lear as consul general
- January 1-17, 1804: A 36-page journal describing the negotiation process in Algiers as well as Algerian food, culture, and customs
- May 1, 1804: "Directions for the Captains of merchant vessels; or vessels bringing the Annuities from the United States to Algiers"
- June 1804: President Thomas Jefferson to Mustapha Pacha, Dey of the City and Regency of Algiers
- August 4, 1804: Orders from Edward Preble concerning Commodore Stephen Decatur and William Bainbridge
- : Instructions for American ships of war to follow when approaching Algiers
- June 4, 1805: Copy of the "Treaty of Peace and Amity" between the United States and the Pasha of Tripoli
- December 31, 1805-June 28, 1806: Letters among Jefferson, Madison, and Sidi Suliman Melli Melli concerning relations with Tripoli
- May 30 and September 7, 1807: Letter from James Madison to Tobias Lear concerning the settlement with Algiers, the Chesapeake Affair, and poor relations with Britain
- August 8, 1812: Letter from Lear to Charles D. Coxe concerning the state of the Mediterranean and being expelled from Algiers
Twenty-seven items relate to the events surrounding Lear's mission to Plattsburg, New York, for a prisoner exchange with the British during the War of 1812. The exchange was largely negotiated between United States Brigadier General William Winder, George Prevost, and British Colonel Edward Baynes, with Lear present to ratify the agreement. United States Army officer Christopher Van Deventer (1788-1838) was among the hostages released. Present are letters from Commissary General of Prisoners General John Mason, Secretary of State James Monroe, and British Commissioner Thomas Barclay, concerning the prisoner negotiations. Included are lists of the American officers and militia men captured at Detroit, a list of the British soldiers held by the United States, and a memorandum of Lear's expenses incurred during the mission. Also of interest is the letter from Lear to his wife describing a trip by steamboat to Albany (July 4, 1814).
Correspondence written in 1815 and 1816 includes 19 letters dealing with settlement of War of 1812 officers' accounts, most to Robert Brent of the War Department, and letters to his wife relating information on his life in Washington and about news of family and friends. The sole letter written after Lear's death concerns his son Benjamin Lincoln Lear's portion of his father's estate (March 21, 1817).
In addition to the letters and journal are two engravings accompanying the letter from August 4, 1804. One shows both sides of the "Preble Medal" (1804), and the other is a portrait of United States Navy officer Edward Preble (1761-1807), engraved by T. Kelly (undated).