Saint Agatha developed as a farming community in the mid-nineteenth century as settlers moved outwardly from the St. John River around Frenchville. Alexandre "Menon" Ouellette was one of the first, such that Long Lake has also been known as "Lac à Menon." In 1889, Bishop James A. Healy assigned a French priest to the predominantly Catholic community, and a parish was founded. A permanent church soon replaced the mission chapel. The parish gave its name to the town, which received its charter in 1899.

The postcard does not give the exact location of this "thoroughfare bridge." The most likely area is the hamlet of Sinclair, where a more recent bridge spans Mud Lake's discharge into Long Lake. No date is given, though the figures are in early twentieth-century (almost certainly pre-World War I) fashions. Efforts to match the two clerical figures with photographs of priests who served Saint Agatha have proven unsuccessful. It may be that they were assigned to the mission of Sinclair.