Jacob Beeson Blair (born April 11, 1821) was an American politician who represented West Virginia in the United States House of Representatives during the Civil War era. A member of the Unconditional Unionist Party, he served as a representative from West Virginia’s 1st Congressional District. His tenure in Congress began on July 4, 1861, reflecting the turbulent period of national conflict and the formation of the new state of West Virginia.

Blair served two terms in the House of Representatives, holding office from July 4, 1861, until March 3, 1865. During these years, he was part of the historical cohort of members of Congress who represented West Virginia after its separation from Virginia and admission to the Union. Identified in congressional records by the bioguide ID B000525, Blair is noted as a former representative whose service coincided with some of the most consequential years in United States history.