The ten largest buildings in the United States by square footage.
These are the ten largest buildings in the United States based upon floor space square footage. Three of these buildings were built for government use, one is a casino, two more house the headquarters of auto makers, one was built by a university, one was built by an insurance company, one was built by Sears and one was built by a real estate development company. For the largest homes in the country see 10 Largest Homes in the United States.
1) The Palazzo in Las Vegas - 6.9 million square feet
The Palazzo is a luxury all-suite casino hotel located at 3325 Las Vegas Boulevard right on the Strip in Las Vegas, Nevada that is the largest building in the United States. The Palazzo has a standard room size of 720 square feet and opened for business on December 30, 2007 and is owned by Las Vegas Sands. This huge casino is some piece of real estate and quite a tourist attraction in Las Vegas.
2) The Pentagon in Arlington County, Virginia - 6.601 million square feet
The Pentagon was designed by architect George Bergstrom and built by contractor John McShain and opened for business on January 15, 1943. Almost 30,000 military and civilians work in the Pentagon daily.
3) K-25 in Oak Ridge, Tennessee - 6.6 million square feet
K-25 is a massive U shaped building that was constructed in Oak Ridge, Tennessee by the Manhattan Project from 1943-1945 as a uranium enrichment facility. After WW II K-25 was turned into a technology park but is currently slated to be demolished sometime in 2011 or 2012.
4) Air Force Plant #4 at Carswell Air Force Base in Fort Worth, Texas - 6.5 million square feet
Image Source (Carswell Air Force Base in Texas)
Air Force Plant #4 is a huge building located at Carswell Air Force base about 5 miles north of Fort Worth, Texas. Air Force Plant #4 today houses operations of defense contractor Lockheed Martin that employs some 17,000 people.
5) Warren G. Magnuson Health Sciences Building in Seattle, Washington - 5.7 million square feet
The Warren G. Magnuson Health Sciences Building is the 5th largest building in the United States and the largest university building in the world as it is located on the campus of Washington University in Seattle, Washington. The building was originally constructed in 1947 and over 50 years has had 20 connected wings added to bringing up to its present size of 5.7 million square feet.
6) Renaissance Center in Detroit, Michigan - 5.5 million square feet
The Renaissance Center is a group of 7 connected skyscrapers that houses the world headquarters of General Motors in Detroit, Michigan. Built from 1977 to 1981 the Renaissance Center is still the tallest building in Michigan today. Located inside is the Detroit Marriott Hotel which is the largest hotel in the Marriott chain with 1,298 rooms.
7) Chrysler Headquarters and Technical Center in Auburn Hills, Michigan - 5.3 million square feet
The Chrysler Headquarters and Technical Center in Auburn Hills, Michigan was built from 1986 to 1991 and contains over 5.1 million square feet over 507 acres just off Interstate 75.
8) Embarcadero Center in San Francisco, California - 4.8 million square feet
The Embarcadero Center is a huge complex consisting of five connected office towers and two hotels located on almost 10 acres along the Embarcadero in San Francisco's financial district. The center was constructed from 1971 to 1989 and over 14,000 people work in the center which includes retail stores, restaurants and a movie theater.
9) Willis Tower in Chicago - 4.5 million square feet
The Willis Tower used to be known as the Sears Tower which was the tallest building in the world for 25 years after it was completed in 1974 at a height of 1,451 feet or 1,729 feet counting towers on top. The Willis Tower is still the tallest building in the United States and 5th tallest building in the world.
10) McDermott Building in San Antonio, Texas - 4.463 million square feet
Image Source (USAA in Colorado Springs similar building to McDermott)
The McDermott Building is owned and managed by the United States Automobile Association or USAA which is a Fortune 500 financial services company located in San Antonio, Texas. McDermott Building was constructed in 1976 and expanded four different times to its present enormous size. It is 4 stories tall and located at 9800 Fredericksburg Road in San Antonio.
For more see 10 Largest Homes in the United States
20 Largest Churches in the World
10 Tallest Statues in the United States
Tallest Lighthouses in the United States