Jacob L. Martin

Jacob L. Martin (died August 26, 1848) was an American diplomat. He held the post of Chief Clerk of the U.S. State Department from July 16, 1840, to March 5, 1841. For just two days, March 4 and March 5, 1841, he held the ad interim chair of the United States Secretary of State.

In 1848 he was appointed chargé d'affaires of the United States to the Holy See. Martin, a Protestant, was chosen over a few candidates who were openly friendly to Vatican. He reached Rome on August 2, 1848, but hesitated to enter the city owing to continuing revolution. Martin presented his credentials to the Holy See on August 19, 1848, but died seven days later and was buried in the city's Protestant Cemetery.