Alexander Thomson (January 12, 1788 – August 2, 1848) was a member of the U.S. House of Representatives from Pennsylvania in the mid-1820s, judge, and law professor.

Alexander Thomson was born at Scotland, Franklin County, Pennsylvania, both of his parents died young.

[1] He studied law under Judge James Riddle in Bedford, was admitted to the bar in 1816, and commenced practice in Chambersburg, Pennsylvania.

[1] He was commissioned president judge of the Sixteenth Judicial District, composed of Franklin, Bedford and Somerset Counties, on June 25, 1827 and served until 1841.

[1][4] Thomson moved to Chambersberg where he purchased a mansion that was used as his residence, offices for his private practices, and a law school.