Incorporated in November of 1870 as the Southern Counties Permanent Building and Savings Society, the company was initiated by local businessmen and farmers who saw the need for providing mortgage financing for the influx of residents attracted to St. Thomas by the railway boom. The construction of the Canada Southern and Great Western- Airline began in 1870. The population of St. Thomas grew from 2,197 in 1871 to 8367 by 1881. The choice of the name “Southern” for the company was advantageous and good branding. The southern counties that it served included Norfolk, Kent, Essex and Lambton, all accessible by the two railways contributing to the boom.

This enterprise became one of the leading institutions of its kind in Canada. Almost all of the directors were from the St. Thomas area and included such notables as Archibald McLachlin, owner of the Evening Journal and Mayor in 1873, and Colin Munro, who was county sheriff and vice-president of the former Bank of the County of Elgin. The Southern Loan Co. was embraced by the local farmers and merchants as something they could call their own.

The company was designed to provide mortgages on real estate for the burgeoning population caused by construction crews, mechanics and trainmen attracted to this community. Advertisements in a local newspaper included this inducement: “Loans to railway men on the installment plan a specialty”. In 1872 the company opened their savings department and in 1892 began issuing debentures for those seeking higher interest rates on longer term deposits.

During the financial crisis of 1901-1903, three loan companies decided to amalgamate into the Southern Loan & Savings Co. The company had commissioned Neil Darrach to build a new headquarters at 372 – 390 Talbot, which was completed in 1901. At one time almost a third of homes built in St. Thomas had financial assistance from the Southern Loan. It prospered because it adhered to a principle of investing in bona fide first mortgages in its domestic market and this market was supported by the steady employment provided by the railways. There was thus a very close connection between the success of the company, the profitability of the railways providing employment, and the prosperity experienced by rail employees.

In 1927, the company was sold to the Huron and Erie Mortgage Co. Employees and the latter moved to the more spacious quarters of the Southern Loan & Savings Co.