The present building was erected in 1910 after a fire destroyed the original M&P bank building. Merchants & Planters Bank and First National Bank merged in March 1932 during the Great Depression, which began in 1929. The Mount Vernon Optic-Herald reported on March 18, 1932, that the merger would give Mount Vernon and Franklin County one of the strongest banks in the section because both banks were in sound condition. As a result, all banking operations were moved to the First National Bank building on the southeast corner of Main and Kaufman, which now houses the Franklin County Library. After the merger, the building continued to serve the community in a number of functions, including as the Mount Vernon Post Office. Under the ownership of Hermon and Bennie Connelly, it became home to Sulphur Springs Loan & Building, Mount Vernon Real Estate & Insurance, and later Jefferson Heritage Bank. In 2001 the operation was purchased by First National Bank, sixty-nine years after the original merger, and the building was renovated in 2005 and continues to serve Franklin County as a First National Bank financial services facility.