David Chambers Mearns, 81, the retired chief of the manuscript division of the Library of Congress, where he worked for nearly six decades, and the editor of "The Lincoln Papers," died Thursday at Goodwin House in Alexandria, where he had lived in recent years. He had a pulmonary disorder.

A native Washingtonian, Mr. Mearns attended George Washington University and the University of Virginia before joining the Library of Congress in 1918. His first job was sorting books in the cellar at a salary of $360 a year. He later held a variety of positions before being named assistant librarian in 1949.

Two years later, he was appointed chief of the manuscript division. At the same time, he held the library's chair in American history and was assistant librarian for the American collections. In the latter post, he coordinated all library acquistions and services relating to American history and civilization.

Although he retired officially in 1967, Mr. Mearns remained at the library as an honorary consultant in the humanities until 1976.

Best known as a Lincoln and Civil War scholar, he said in a Washington Post interview in 1948 that he became interested in Lincoln "almost in self-defense" while working in the library's reference room in the late 1920s, where he had to handle correspondence dealing with the president.

"The Lincoln Papers came here shortly after that and I tried to learn about them, but couldn't. It was very tantalizing. I used to see Robert Todd Lincoln [the president's son] in the library, too, and of course that was a spur to the imagination," Mr. Mearns said.

In July 1947, after 82 years, Lincoln's papers, which had been gathered by Robert Todd Lincoln and jealously guarded by him during his own lifetime and for 21 years thereafter, were opened to the public for the first time.

A week later, Mr. Mearns began work on his book about them. It was the first authoritative report on the vast Lincoln collection, with an introduction by Carl Sandburg.

Mr. Mearns was the author of 12 other books, including, "The Story Up To Now, The Library of Congress 1800-1946," and numerous publications on Lincoln. He also was a frequent contributor to New York and Washington newspapers.

He was active in a number of professional and other associations and served on advisory committees on the papers of Benjamin Franklin, Thomas Jefferson and Woodrow Wilson.

Mr. Mearns' first wife, the former Mildred Sellars Haines, died in 1945.

In 1951, he married the former Mary Hume Richardson, a former special assistant at the Library of Congress, who survives.

Besides his wife, who lives at Goodwin House, survivors include a daughter by his first marriage, Anne Mearns Jacoby, also of Alexandria, two granddaughters, and two great-grandsons.