Its advertisement in the Official Guide promised "The only hotel within the grounds" of the exposition, "under the supervision of the Exposition management." Emmett W. MacConnell and associates built it near the Baker Street entrance, with about 638 rooms, at a cost of about $375,000. It opened on January 15, 1915, a month before the fair, with every outside room claiming a private bath, telephone and steam heat, and rates from $1 to $5 a day on the European plan.
Todd called it "the best hotel ever built in the grounds of an exposition." Its grill and ballroom often served as a convention hall, and many delegates made it their exposition home. It was also the fair's biggest business: its gross of over $675,000 was the largest of the more than 450 concessions. Meals were famously reasonable, with breakfast at 75 cents, lunch at $1.00 and dinner at $1.50, all "generous meals of several courses," and prices were cut further toward the close.
Just north of the Inn lay the Musical Concourse, a terraced rectangle about 200 by 350 ft that could seat some 11,000 people on benches around a circular bandstand 41 ft across.