| State House: | Mississippi |
| District: | Claiborne County |
| Alongside: | Henry G. Johnston |
| Term Start: | October 6, 1817 |
| Term End: | February 6, 1818 |
| Speaker: | 1st |
| Termstart2: | October 6, 1817 |
| Termend2: | February 6, 1818 |
| Successor2: | Edward Turner |
Thomas A. Barnes was a state legislator in Mississippi. He served as Speaker of the Mississippi House of Representatives during the first General Assembly held in Mississippi from October 6, 1817 to February 6, 1818.[1] Barnes had previously been a member of the Legislative Council of the Mississippi Territory representing Clairborne County[2] and was president of the council from 1809 to 1810, then again from 1812 to 1815.[3] In 1815 he resigned due to bad health.[4]
He lived in Port Gibson, Mississippi.[5]
He was involved with negotiations over commerce on the Mississippi River and a proposal for election districting.[6]