Mile High Stadium was a sports arena in Denver, Colorado, in professional use until 2001. Most notably the home of baseball’s Colorado Rockies and football’s Denver Broncos, Mile High Stadium was known as Bears stadium from 1948, when it opened, until 1968. Since known as Mile High Stadium, it has also been home to the Colorado Rapids of Major League Soccer, the Denver Gold of the United States Football League, and the Denver Zephyrs and Denver Bears of Minor League Baseball. The stadium has been known as a home field advantage in baseball due to the lighter air, and has caused visiting athletes trouble due to the same reason.

The stadium is named Mike High Stadium because of its position exactly one mile (1.6 km) above sea level, along with the rest of the city of Denver. It was built in 1948 by Bob Howsam as a minor league baseball venue. It initially featured a 17,000-seat grandstand stretching the outfield fences. In the 1950s, Bears Stadium increased to 23,000 seats, then close to 35,000 seats to accommodate a proposed professional baseball team for the city of Denver. Mile High Stadium first saw a football team, however, when the Denver Broncos became a member of the American Football League.

In 1968 the stadium was sold to the city of Denver, at which point it was renamed Mile High Stadium and had its first upper deck added. With the addition of these extra seats, the capacity was raised to 50,000. By 1974, a $25 million US Dollars (USD) bond issue and a third deck raised the capacity yet again, this time to 63,000 seats, and then again to 75,000 by 1977. Retractable triple deck stands along the east side of the stadium allowed Mile High Stadium conversion capabilities from a football field to a baseball field. The eastern stands could be included to form a horseshoe for football games, or removed to open the field for a baseball game. With the adding of luxury suites in the 1980s, and the Colorado Rockies in 1993, Mile High Stadium thrived until the Broncos moved to the neighboring Invesco Field in 2001.

Known as a homerun hitter’s park in Major League Baseball, Mile High Stadium was only played at for two years by the Colorado Rockies, before they moved to Coors Field. It has been suggested that the light air of the stadium, elevated a mile over sea level, has led to increased home runs at the ballpark. Indeed, the stadium has seen career years in home runs by many players, and has features some homerun filled games and seasons, but it has never been conclusively proved that the light air allows the baseball to travel farther off of the bat. One study has suggested that the lighter air accounts only for an additional four feet of travel from a struck baseball.