Longest serving U.S. attorneys general

Eric Holder looks on before the "We Are One: The Obama Inaugural Celebration At The Lincoln Memorial" at the National Mall in Washington, D.C., Jan. 18, 2009.

Holder, the nation's first black attorney general, is resigning after six years on the job. He is currently the fourth-longest serving U.S. attorney general (2,060 days). The following are the longest serving U.S. attorneys generals in U.S. history.

10. William F. Smith

Attorney General William French Smith is seen on July 30, 1981, as he presents President Reagan's immigration package to a Joint House-Senate Judiciary Sub-committee on Immigration in Washington.

Smith served 1,492 days between Jan. 23, 1981 and Feb. 23, 1985.

9. Thomas Gregory

Thomas Gregory served as attorney general for 1,643 days under President Woodrow Wilson between Sept. 3, 1914 and Mar. 4, 1919.

8. Benjamin F. Butler

7. Herbert Brownell, Jr.

President Dwight Eisenhower, center, meets with Attorney General Herbert Brownell, left, and FBI Chief J. Edgar Hoover at the Summer White House in Denver, Colorado on Sept. 12, 1954.

Brownell served as attorney general 1,752 days, from Jan. 21, 1953 to Nov. 8, 1957.

6. Caesar Rodney

Caesar Augustus Rodney is seen in an 1800 etching.

Rodney served as attorney general from Jan. 20, 1807 to Dec. 5, 1811.

5. Charles Lee

Charles Lee was U.S. attorney general for 1,910 days from Dec. 10, 1795 to Mar. 4, 1801.

He was brother to Gen. Henry "Light Horse Harry" Lee and uncle to Robert E. Lee.

3. Homer Cummings

Homer Cummings leaves the White House following a conference called by President Roosevelt Monday to discuss a wide range of legislative problems, Jan. 21, 1935.

Cummings was U.S. attorney general for 2,130 days, from March 4, 1933 to Jan. 2, 1939.

2. Janet Reno

U.S. Attorney General Janet Reno, right, talks to the media in Washington, D.C. on April 22, 2000. With her is Deputy Attorney General Eric Holder.

Reno served as attorney general for 2,871 days, from March 12, 1993 to Jan. 20, 2001.

1. William Wirt

William Wirt is seen in an engraving by James Barton Longacre.

Wirt was the longest serving U.S. attorney general, serving 4, 126 days, from Nov. 15, 1817 to Mar. 3, 1829.