Alexander Irvin (January 18, 1800 - March 20, 1874) was a United States Representative from Pennsylvania. He was born in Penns Valley, Center County, Pennsylvania. He attended the public schools of the area and moved to Curwensville in 1820 and to Clearfield, Pennsylvania in 1826. He engaged in mercantile and lumbering pursuits and was the treasurer of Clearfield County from 1828-1830.
Irvin was a member of the State senate in 1837 and 1838. He was named the prothonotary of the court of common pleas in 1842. He was the recorder of deeds and register of wills of Clearfield County fom 1842-1844. He was elected as a Whig to the Thirtieth Congress (March 4, 1847 - March 3, 1849). He was not a candidate for renomination. He was a United States marshal for the western district of Pennsylvania from January 17 to September 3, 1850, when he resigned, being succeeded by his brother, William Irvin. He was named a delegate to the Republican National Convention in 1872. He than became engaged in mercantile pursuits at Clearfield, Clearfield County, Pennsylvania until his death in 1874. He was buried in the Reed addition to the Old Graveyard.