Within a year after its founding, the bank had opened three branches. After consolidating its presence in the Eastern Townships, it opened branches elsewhere in Quebec and in Western Canada (including Grand Forks, British Columbia and Taber, Alberta). By 1911, it had over 100 branches. To increase its presence on a national scale, its shareholders agreed to merge, effective March 1, 1912, with the Canadian Bank of Commerce, which later became Canadian Imperial Bank of Commerce.
The former branch of the Eastern Townships Bank at the corner of Saint Catherine Street and Crescent Street in Montreal was used as the flagship store for Parasuco, a line of denim clothing. The building is now vacant.
The former head office building of the Eastern Townships Bank in Sherbrooke, Quebec is now an art museum, the Musée des beaux-arts de Sherbrooke.