Question: In what geographical region can the David McCullough Bridge be found?

full_context: Document 1: List of crossings of the Monongahela River: This is a complete list of current bridges and other crossings of the Monongahela River starting from Pittsburgh, Pennsylvania, where the river helps to form the headwaters of the Ohio River, and ending in Fairmont, West Virginia, where the West Fork River and Tygart Valley River combine to form the Monongahela.
Document 2: George D. Stuart Bridge: The George D. Stuart Bridge (commonly known as the Tarentum Bridge) is a steel deck truss bridge that carries vehicular traffic across the Allegheny River between New Kensington and Tarentum in the U.S. state of Pennsylvania.
Document 3: French Creek (Allegheny River tributary): French Creek (also known as the Venango River) is a tributary of the Allegheny River in northwestern Pennsylvania and western New York in the United States.
Document 4: Deer Creek (Allegheny River tributary): Deer Creek is a tributary of the Allegheny River located in both Allegheny and Butler counties in the U.S. state of Pennsylvania.
Document 5: Cowanshannock Creek: Cowanshannock Creek (the eastern section is sometimes referred to as the North Branch Cowanshannock Creek) is a tributary of the Allegheny River in Armstrong and Indiana counties, Pennsylvania in the United States.
Document 6: Fort Duquesne Bridge: The Fort Duquesne Bridge is a steel bowstring arch bridge that spans the Allegheny River in Pittsburgh, Pennsylvania. It was colloquially referred to as "The Bridge to Nowhere". It was constructed from 1958-1963 by PennDOT, and opened for traffic October 17, 1969 with its predecessor Manchester Bridge (located closer to the tip of Point State Park) closing that same day (it was demolished in the autumn of 1970). The bridge was given the name "The Bridge to Nowhere" because the main span was finished in 1963, but due to delays in acquiring right of ways for the northern approach ramps, it did not connect on the north side of the Allegheny River. The total cost was budgeted at $5 million in 1962. The lack of approach ramps meant the bridge ended in midair, rendering it useless. The northwestern ramps were completed in 1969, allowing access to Pennsylvania Route 65. The northeastern ramps were completed in 1986, with the construction of the northern section of Interstate 279 (North Shore Expressway) which runs through Downtown Pittsburgh's Golden Triangle and north towards Interstate 79.
Document 7: Washington Crossing Bridge (Pittsburgh): The Washington Crossing Bridge, commonly known as the Fortieth Street Bridge, is an arch bridge that carries vehicular traffic across the Allegheny River between the Pittsburgh neighborhood of Lawrenceville and the suburb of Millvale.
Document 8: Cheat River: The Cheat River is a tributary of the Monongahela River in eastern West Virginia and southwestern Pennsylvania in the United States. Via the Ohio River, the Cheat and Monongahela are part of the Mississippi River watershed. Owing to the ruggedness of the surrounding Allegheny Mountains, the Cheat remains largely remote with few settlements or developments along its banks. Its headwaters are in the Cheat-Potomac Ranger District of the Monongahela National Forest.
Document 9: Pucketa Creek: Pucketa Creek is a tributary of the Allegheny River located in both Allegheny and Westmoreland counties in the U.S. state of Pennsylvania.
Document 10: South Tenth Street Bridge: South Tenth Street Bridge, most often called the Tenth Street Bridge, but officially dubbed the Philip Murray Bridge, is a suspension bridge spanning the Monongahela River in Downtown Pittsburgh, Pennsylvania. The bridge was renamed on Labor Day 2007 for Philip Murray, the first president of the United Steelworkers of America.
Document 11: David McCullough Bridge: The David McCullough Bridge, commonly and historically known as the 16th Street Bridge, is a steel trussed through arch bridge that spans the Allegheny River in Pittsburgh, Pennsylvania.
Document 12: Brady Street Bridge: The Brady Street Bridge, also known as the South 22nd Street Bridge, was a steel bowstring arch bridge in Pittsburgh, Pennsylvania, which crossed over the Monongahela River at South 22nd Street. It was replaced by the Birmingham Bridge in 1976, and was demolished on May 29, 1978. The bridge's main span was a tied arch with a suspended road deck, with two through-truss side spans, carrying two traffic lanes between Brady Street on the Pittsburgh side and South 22nd Street on the south side. Approach viaducts were built at either end. The bridge was built by the Schultz Bridge and Iron Company.
Document 13: Tionesta Creek: Tionesta Creek is a tributary of the Allegheny River in Forest, Clarion, Warren, McKean, and Elk Counties in Pennsylvania in the United States. Together with its West Branch, Tionesta Creek is long, flows generally south, and its watershed is in area.
Document 14: Homestead Grays Bridge: The Homestead Grays Bridge, also known as the (Homestead) High Level Bridge, was built in 1936 and spans the Monongahela River between Homestead Borough and the southernmost tip of Pittsburgh's Squirrel Hill neighborhood. It is notable as the first bridge to incorporate the Wichert Truss, which uses a quadrilateral shape over each support, into its design. This made the truss statically determinate, so that forces in the structural members could be calculated.
Document 15: Allegheny River: The Allegheny River (/ ˌæləˈɡeɪni / AL - ə - GAY - nee) is a principal tributary of the Ohio River; it is located in the Eastern United States. The Allegheny River joins with the Monongahela River to form the Ohio River at the ``Point ''of Point State Park in Downtown Pittsburgh, Pennsylvania. The Allegheny River is, by volume, the main headstream of the Ohio River.
ground_truth: Eastern United States
sub_queries: What river does David McCullough Bridge cross? Answer: Allegheny River
where is Allegheny River located on a map Answer: Eastern United States