List of most expensive U.S. public works projects
Below is a list of so-called megaprojects that are among the most expensive in U.S. history.
The following list includes projects to build new highways or improve existing ones, including roadways, bridges, and tunnels. It includes only projects that are underway or completed. Additionally, projects with multiple independent segments (e.g., I-69 Indiana-Texas Extension, Trans-Texas Corridor) are not included, though individual segments may or may not make the list.
- Big Dig (1992–2006), Boston, Massachusetts, $14.6 billion
- San Francisco–Oakland Bay Bridge East Span Replacement (2002–13), San Francisco/Oakland, California, $6.3 billion
- Mon-Fayette Expressway (1988–2012), southwest Pennsylvania and northern West Virginia, $5.0 billion 
- Ohio River Bridges Project (2005–20), Louisville, Kentucky, and southern Indiana, $4.1 billion
- Central Texas Turnpike (2001–7), area around Austin, Texas, $3.6 billion
- Intercounty Connector (2007–11), Montgomery County, Maryland, $2.57 billion
- Woodrow Wilson Bridge Replacement (1999–2008), Washington, D.C., Northern Virginia, and southern Maryland, $2.5 billion
- I-4 Ultimate corridor reconstruction (2015-2021), Orlando, Florida, $2.3 billion
- Alaskan Way Viaduct replacement tunnel, 2012–15, Seattle, Washington, $2 billion – $4 billion 
- Interstate 69 Extension SIU #3 (2008–18), Evansville to Indianapolis, Indiana, $1.8 billion
- Wekiva Parkway (2013-2021), Orlando, Florida, $1.6 billion
- I-95 New Haven Harbor Corridor Reconstruction (2001–16), New Haven, Connecticut, $1.4 billion
- E-470 (1991–2003), Denver, Colorado, $1.2 billion
- Central Artery/Tunnel Project Website
- Boston’s ‘Big Dig’ opens to public, MSNBC, December 20, 2003
- Turnpike panel says high costs imperil Mon-Fayette, Southern Beltway projects, Pittsburgh Post-Gazette, April 27, 2007
- Louisville Bridges Cost Now $4.1 Billion, The Urbanophile, October 6, 2007
- Federal Highway Administration, Central Texas Turnpike Fact Sheet
- Maryland Department of Transportation ICC Website
- Woodrow Wilson Bridge Replacement Website
- Tracy, Dan (17 February 2015). "I-4 Ultimate overhaul gets ceremonial start". Orlando Sentinel. Retrieved 18 February 2015.
- Seattle Approves Tunnel
- I-69 Indianapolis to Evansville Corridor Study
- "Frequently Asked Questions". Wekiva Parkway. Florida Department of Transportation & Central Florida Expressway Authority. Retrieved 18 February 2015.
- COG panel OK with $498M spike in Q bridge cost, New Haven Register, August 9, 2007
- Final leg of E-470 nears completion, Denver Business Journal, December 13, 2002