Kenneth Price, co-director of the Walt Whitman archive, speaks as the National Archives unveils newly discovered documents written by Whitman. (Bill O’Leary/The Washington Post) (JESSICA RINALDI/REUTERS)

Whitman came to Washington from Brooklyn, where he lived, in 1862 after his brother, George, was wounded in the Battle of Fredricksburg. The poet stayed on in the capital after his brother recovered, working part time in the paymaster’s office and visiting wounded soldiers in Washington hospitals. He returned to Brooklyn in June 1864 because of poor health, but then came back to Washington in January 1865 and served as a clerk in the Interior Department and the attorney general’s office.

The archives said a Whitman scholar, Kenneth Price of the University of Nebraska at Lincoln, discovered some 3,000 documents in Whitman’s handwriting during research at the archives in 2008 and 2009.

The documents are mainly letters from officials that Whitman copied for the record into ledger books. But Price said Whitman may have helped author some of the original letters, and thus might have had a small hand in influencing government policy in the years after the war.

David Ferriero, the Archivist of the U.S., called the discovery a major find. Price said he was “electrified” when he realized that the handwriting in the ledger books was Whitman’s.

Whitman is one of America’s great poets, and is considered the poet of the Civil War.