List of historic mansions in the United States

Lavish mansions were built by some of the richest people in the United States before, during, and following the Gilded Age up until the outbreak of World War II. These estates were raised by the nation's industrial, financial and commercial elite, who amassed great fortunes in era of expansion of the tobacco, railroad, steel, and oil industries coinciding with a lack of both governmental regulation and the absence of a personal income tax. The manor homes and city seats were designed by prominent architects of the day and decorated with antiquities, furniture, and works of art from the world over.

Source: Wikipedia — List of historic mansions in the United States (CC BY-SA 4.0)