James Dabney Thornton (January 19, 1823 – September 27, 1902) was an American lawyer and judge who served as associate justice of the Supreme Court of California from 1880 to 1891.

[5] There, he started a law firm with his father-in-law and John James Williams, whom he had befriended in Richmond, Virginia.

[9] During the Civil War, he refused to take the oath of allegiance to the United States, as did Solomon Heydenfeldt, who was born in Charleston, South Carolina.

[11] In 1878, James Thornton was appointed judge of the Twenty-third district court by Governor William Irwin.

[18][19] In November 1890, just prior to the end of his term, he ran unsuccessfully as a Democrat for judge of San Francisco County Superior Court.