The Northwest Pavilion, located at 151 E. Randolph Street, houses the Millennium Park Welcome Center and an Exelon energy display. It contains the Millennium Park offices, and public restrooms. The three-story Northwest Pavilion is the largest of the four pavilions, with 6,100 square feet (566.7 m2), and is the only pavilion that does not provide access to the parking garage below. The Northwest Pavilion has 460 photovoltaic modules to harness solar energy, houses recycling facilities, and its "interior finishes and construction materials are derived from renewable resources".
The Millennium Park Welcome Center in the Northwest Pavilion offers guides to the park and wheelchairs. It houses exhibitions on parks and energy, and has interactive displays on how the pavilions' solar panels function and on renewable energy. There are exhibits with interactive web-based touch screens that depict the city's use of solar energy, and a dynamic multi-screen video presentation on electricity generation and usage. The building's atrium includes a sculpture by Chicago-based artists Patrick McGee and Adelheid Mers with three backlit 9-foot (2.7 m) two-way mirrors. The sculpture, titled Heliosphere, Biosphere, Technosphere, is "designed to interpret the links between the Earth's atmosphere, the solar system and scientific applications". It is the only permanent work of art by Chicago artists within the park.