The Athenaeum was located on the northwest corner of Palisade avenue & Engle streets, was a brick structure, three stories high, with a mansard roof which converted attic space into a sort of additional story. It was a big building. Seventy-five feet square, something tremendous for the time and place. There were stores on the ground floor on the avenue side, and the upper stories were laid out as offices fronting on Palisade Avenue. The entrance lobby, on the Engle street side was insignificant in dimension, the stairway leading to the auditorium on the rear of the second floor leaving much to be desired in points of safety and convenience. With a hall that had a seating capacity of 800, The Athenaeum opened in the early part of 1870 with a grand concert.