The Ann W. Richards Congress Avenue Bridge (formerly known simply as the Congress Avenue Bridge) crosses over Lady Bird Lake in Austin, Texas. Before construction of the Longhorn Dam was completed in 1960, the bridge crossed the Colorado River from which Lady Bird Lake is impounded. The bridge was known as the Congress Avenue Bridge from the construction of the first span across the Colorado River at that location in the late 19th century until November 16, 2006, when the Austin City Council renamed the current bridge in honor of Ann W. Richards, the 45th Governor of Texas and a long-term resident of Austin. The bridge is a concrete arch bridge with three southbound and three northbound vehicle lanes and sidewalks on both sides of the bridge.

Ann W. Richards Congress Avenue Bridge is home to the world's largest urban bat colony which is composed of Mexican free-tailed bats. The bats reside beneath the road deck in gaps between the concrete component structures. They are migratory, spending their summers in Austin and the winters in Mexico. According to Bat Conservation International, between 750,000 and 1.5 million bats reside underneath the bridge each summer. Since Austin's human population is about 750,000, there are more bats than people in Austin during summer.
The nightly emergence of the bats from underneath the bridge at dusk, and their flight across Lady Bird Lake primarily to the east, to feed themselves, attracts as many as 100,000 tourists annually. Tourists can see the bats from the bridge, from the sides of the river and from boats.

A study made in 1999 by Dr. Gail R. Ryser and Roxana Popovici concludes that the economic impact of the bats to Austin city is $7.9 million each year. Today, businesses are using the bats as a symbol for Austin.

A project, called "Bats and Bridges", has been put in place by the Texas Department of Transportation, in cooperation with BCI, to study the best way to make bridges habitable for bats.

The Austin Ice Bats minor-league hockey team was named in honor of the bridge's bats.

The song "Bats" by Kimya Dawson and rapper Aesop Rock was inspired by the immense number of bats that reside under the bridge.