Abel Parker Upshur (June 17, 1790 – February 28, 1844) was a lawyer, planter, slaveowner, judge and politician from the Eastern Shore of Virginia. Active in Virginia state politics for decades, with a brother and a nephew who became distinguished U.S. Navy officers, Judge Upshur left the Virginia bench to become the Secretary of the Navy and Secretary of State during the administration of President John Tyler, a fellow Virginian. He negotiated the treaty that led to the 1845 Texas annexation to the United States and helped ensure that it was admitted as a slave state. Upshur died on February 28, 1844, when a gun on the warship USS Princeton exploded during a demonstration.