Ely Hall is a two-story Richardsonian Romanesque classroom and laboratory building on the campus of Vassar College in the town of Poughkeepsie, New York, US.

The structure houses Vassar's Department of Earth Science and Geography, the A. Scott Warthin Jr. Museum of Geology and Natural History, and the Aula, a spacious and frequently used gathering space.

Originally known as the Alumnae Gymnasium, the building was erected as a response to the perception that Vassar's physical education program was falling behind those of other Seven Sisters colleges.

Plans for the hall were made, scrapped, and remade as the college and alumnae benefactors struggled to raise sufficient funds.

The New York and Boston alumnae clubs began an attempt to raise $20,000, which they believed to be an adequate sum to pay for a new home for athletics at the school.

The Vassar Board of Trustees formed a subcommittee and attempted to find solutions, including modifying Tubby's designs.

[2] Tubby's initial plans were scrapped in October 1888 in favor of a pared-down version of the new building that was to include only dressing rooms and a single exercise hall, totaling no more than the available $20,000 in cost.

[8] Provided Vassar's society of alumnae would able to produce an additional $2,500 for improvements, the building was planned to open at the start of the athletic season in November.

[9] Once the money was raised and the construction flaws were fixed, the Alumnae Gymnasium opened on November 23 with a Philaletheis production of W. S. Gilbert's play Engaged.

[13] The building was further renovated in 1994 by Olson Lewis Architects & Planners, Inc.[14] The Alumnae Gymnasium was designed in the Richardsonian Romanesque style.

Recent renovations have returned the Aula space to its original state, with visible rafters, terra cotta accents, and hardwood floors.

He stipulated that the new structure's location would not impede the view from the Vassar College Observatory but that it would be close enough to be heated by the nearby power plant.