The contract to build the park's premiere structure, the Pavilion, was let in April of 1909.
The park first opened in July, 1909, as indicated by the following newspaper article from the St. Tammany Farmer. Click on the image to enlarge the type.
Here are some pictures of the entrance to Bogue Falaya Park. The first one is in the 1910's.
Photo by Doug Harrison
Bogue Falaya Park Pavilion