The US doesn't do megaprojects by halves, investing years – sometimes even decades – and billions of dollars in the development of bridges, railroads, airports, and more.

From icons of infrastructure such as the Golden Gate Bridge to modern marvels such as the replacement Yankee Stadium, read on to discover America's most expensive public and private construction works of all time.

We'll also reveal how much they would cost to build in today's money, with all dollar amounts in US dollars. 

Measuring more than 4,200ft long, San Francisco's Golden Gate Bridge was completed in 1937 and promptly became the world's longest suspension bridge, a title it retained until 1964.

Famous around the world, this amazing feat of engineering cost a total of $35 million in 1937, which equates to $767 million today. 

With the exception of the Sausalito Lateral approach road (today known as Alexander Avenue), which was built as a federal Works Progress Administration (WPA) project, there was no state or federal funding involved in building the Golden Gate Bridge.

Part of the Central Florida Beltway, the Wekiva Parkway (also known as Florida State Road 429) opened in January 2024 after more than a decade of construction. The total cost came to $1.6 billion.

The 25-mile-long highway passes through the environmentally sensitive Wekiva River Basin, adding to the complexity and expense of the work. Most of the project has been financed by tolls on the new highway. 

Extension 470, more commonly known as E-470, is a 47-mile-long toll road that curves around the eastern edge of the Denver metropolitan area in Colorado. 

Built in sections and completed in 2003, E-470 cost a total of $1.5 billion, which works out to be around $2.6 billion when adjusted for inflation.

It's one of the first privately built, owned, and operated toll roads in the US.

Completed in 1869, the First Transcontinental Railroad spanned 1,912 miles, connecting America's rail network from Omaha, Nebraska, to Sacramento, California. 

Two companies took on this massive undertaking: the Union Pacific built the line westward and the Central Pacific worked eastward, with the two meeting in Utah.

Compensation included land rights and government bonds, meaning that there are no reliable figures for the exact cost of the railroad. One estimate puts the total at around $111.5 million, which is $2.6 billion today.

Another construction triumph of the Depression Era, the Hoover Dam was built between 1931 and 1936 at a cost of $49 million.

Its power plant and generators cost an additional $71 million, resulting in a grand total of $120 million. That's around $2.7 billion in today's money.

As well as providing tens of thousands of jobs over the decades, the colossal dam is a key flood control safeguard and a major supplier of hydroelectric power in the region. In fact, the sale of electrical power generated by the Hoover Dam had paid back its construction cost, complete with interest, by 1987.

The Alaska Highway was completed in 1942 – a remarkable achievement given that the US was at war at the time.

The final bill for the 1,700-mile highway was $138 million, the equivalent of $2.7 billion today. The gruelling project required a crew of more than 25,000 men to work seven days a week.

This extensive highway project focused on the reconstruction and widening of a 7-mile stretch of highway between Interstate 95 (I-95) between New Haven and Branford, Connecticut. By the time the work was finished in 2018, it had racked up a cost of $2.2 billion, which is about $2.8 billion today. 

The program also included building a new 10-lane Pearl Harbor Memorial Bridge over the Quinnipiac River. This was to replace the existing bridge, which dated back to the 1950s. 

With a length of 4,260ft, the Verrazzano-Narrows Bridge snatched the Golden Gate's crown and became the longest suspension bridge in the world upon its completion in 1964. It held on to the title for 17 years before being usurped by the UK's Humber Bridge in 1981.

The Verrazzano-Narrows crossing, which connects Brooklyn and Staten Island while spanning New York Harbor, cost $305 million to build, which is $3.1 billion when adjusted for inflation.

Also known as the Intercounty Connector, this 18-mile road project in Maryland was initially proposed back in 1969 but wasn't approved for construction until the early 2000s.

The tolled highway connects I-270 in Gaithersburg, Montgomery County, and US 1 in Laurel, Prince George's County. By the time the work was finished in 2014, it had cost $2.4 billion, which is around $3.2 billion today.

The largest highway infrastructure project in Florida's history, the I-4 Ultimate focused on improvements to a 21-mile-long stretch of Interstate 4 in the Orlando area.

The program included reconstructing 15 interchanges, building 53 new bridges, and replacing or widening another 87 bridges. It also introduced four express toll lanes. Work began in 2015 and finished in 2021 at a total cost of $2.9 billion, or $3.4 billion today.

This ambitious project aimed to expand the US freight rail network across 13 states from Louisiana to New Jersey, covering around 2,500 miles.

In a public-private partnership between the government and Norfolk Southern Railway, it also included expanding or building terminals in 11 markets, allowing rail freight to compete with the long-haul trucking services offered along nearby interstates and highways.

Cost estimates for the program were $2.5 billion when many of the initial terminals opened in 2012. That's $3.4 billion in today's money.

The replacement Yankee Stadium in New York cost $2.3 billion to construct in 2009, making it the most expensive stadium ever built at the time.

Controversially, a hefty $1.2 billion of public money helped fund the project. Adjusting that for inflation, the stadium cost a total of $3.4 billion in today's dollars.

One of the world’s largest drawbridges, the Woodrow Wilson Memorial Bridge (also referred to as the Woodrow Wilson Bridge) carries 12 lanes of traffic over the Potomac River between Alexandria, Virginia, and Oxon Hill, Maryland.

Plans for replacing the original bridge, which opened in 1961, had been in motion since the 1980s, although construction didn't begin until 2000. The new bridge opened to traffic in 2008 at a total cost of $2.4 billion, or $3.5 billion today.

This complex megaproject included two new bridges, as well as the construction of roadways, freeway interchanges, a tunnel, and other facilities that connect Indiana and Kentucky over the Ohio River.

Shared across both states, all of this new infrastructure was delivered in two programs, with Indiana leading the East End Crossing and Kentucky leading the Downtown Crossing project. Both were completed by 2016 for a grand total of $2.8 billion, which is $3.7 billion today.

Four different road projects make up the Pennsylvania Turnpike Commission’s Mon/Fayette Expressway, with three already completed.

Facing funding setbacks, the last part of the program was delayed for a number of years. Although construction started in 2023 on the first section of the final and largest road, the second section of this road, and substantial completion of the entire project, are not expected before 2028.

According to 2019 estimates, the Commission has so far spent $1.9 billion, which is $2.4 billion with inflation factored in. The next phase is estimated to cost a further $1.3 billion.

After 16 years of construction, this massive and long-awaited 142-mile extension of Interstate 69 from Evansville to Indianapolis opened to the public in summer 2024. 

The milestone marked the completion of construction on the sixth and final section of the overall project, which was announced in 2008. Work on this last stretch cost $2 billion and started in 2019. It includes 26 miles of interstate, 10 new interchanges and more than 35 miles of local access roads. The overall program's cost totals $4 billion.

This wide-ranging expansion of Interstate 10 in Houston was carried out over a period of five years between 2003 and 2008, costing a total of $2.8 billion, or $4.1 billion when adjusted for inflation.

Increased traffic in the city meant that congestion on the roads was lasting for up to 11 hours a day, so a fix was badly needed. Major reconstruction work along a 12-mile section expanded the Katy Freeway to six general lanes in each direction, with two toll lanes.

At a length of 1.7 miles, this tunnel project was beset by problems ever since excavation work first began beneath Seattle in July 2013.

Almost immediately after the work started it was stalled for two years after the tunnel boring machine – nicknamed "Bertha" and, at the time, the largest of its type in the world – needed repairs to its main bearing.

The estimated completion date for the work, which now operates as the State Route 99 tunnel, was shifted from 2015 to 2019. The total cost came to $3.3 billion, or $4.1 billion when adjusted for inflation.

The Central Texas Turnpike project saw the construction of three toll roads (now known as the Austin Area Toll Roads) in Austin and along the Austin-San-Antonio corridor.

They opened to traffic in 2008 after six years of construction, with the work costing around $3.3 billion. That's $4.8 billion with inflation.

Officially the tallest building in the Western Hemisphere, One World Trade Center is the principal building in the rebuilt World Trade complex in New York City.

Standing at 1,776ft tall – representing the 1776 signing of the Declaration of Independence – the skyscraper was completed in 2014 at a cost of around $3.8 billion, which is $5.1 billion today.

Owned by the Port Authority of New York and New Jersey, the reconstruction has been paid for by a combination of public funding and insurance money.

Plans for New York’s Second Avenue Subway date back to the 1920s. However, financial roadblocks throughout the 20th century reduced the 8.5-mile project into four phases.

Phase 1, which comprises 1.8 miles of subway line and three stations, opened in 2017 at a cost of $4.5 billion, or $5.8 billion today.

New York Governor Kathy Hochul had previously announced that Phase 2 would be moving forward, extending the subway to 125th Street in Harlem. But progress has since halted due to a lack of funding. 

Measuring in at 7,710ft, the replacement Evergreen Point Floating Bridge is the longest floating bridge in the world.

Completed in 2016, the six-lane bridge carries State Route 520 across Lake Washington from Seattle to its eastern suburbs. This megaproject also included road widening to add high occupancy vehicle (HOV) lanes, improved bridge approaches, and other traffic infrastructure improvements.

The total package came to $4.5 billion, which is $5.9 billion when adjusted for inflation. 

This extension to the Silver Line in Washington, D.C., connected the city’s downtown with Dulles International Airport, adding a total of 11 new stations.

Construction took place in two phases, with the final grand opening of the 23-mile line taking place in 2022. The total project cost around $6 billion ($6.5 billion with inflation), much of which has been funded by drivers on adjacent toll roads.

LaGuardia once held the dubious honour of being ranked among the very worst of the USA's airports, with America's then-VP Joe Biden comparing it to arriving at "some third-world country" in 2014.

The following year, New York's then-governor Andrew Cuomo launched an ambitious overhaul of the NYC airport, plugging billions of dollars billion into improving its terminals and facilities. 

Two-thirds of the cost has been covered by private funding, and since reaching completion in 2022, the airport is now winning awards and acclaim. The total amount spent was $8 billion, or when adjusted for inflation, $8.6 billion. 

Replacing a section of the seismically unsound eastern span of the Bay Bridge was to become one of the most expensive public works projects in Californian history, setting the state back an eye-watering $6.5 billion. That's $8.8 billion when adjusted for inflation – and significantly higher than the $250 million price tag that was originally attached to the work back in 1995.

Construction started in 2002 and wasn't completed until 2013.

Work on the San Francisco’s Bay Area Rapid Transit (BART) rail system started in June 1964.

With a number of sections built underground, the project included the construction of the underwater Transbay Tube, a 3.8-mile-long tunnel made up of 57 giant steel and concrete sections immersed beneath San Francisco Bay itself. 

The first section of the system went into operation in 1972 and reportedly carried 100,000 passengers across its 28 miles of track in just five days. As of the mid-1970s, it was estimated that it had cost $1.6 billion to build, which is around $12.1 billion today.

New York’s East Side Access was the Metropolitan Transportation Authority’s (MTA) largest ever capital project. The work included the addition of 40 miles of new tracks to the Long Island Rail Road (LIRR) and the erection of a massive new terminal beneath Grand Central.

Construction began in 2001 with 2009 floated as the expected completion date. However, this deadline came and went and the project finally opened more than a decade later in in 2023, having racked up a bill of nearly $12 billion ($12.4 billion with inflation).

The Central Artery/Tunnel Project – nicknamed the "Big Dig" – replaced Boston’s tired six-lane elevated Central Artery with a 3.5-mile underground highway.

The work also included the construction of two bridges across the Charles River, as well as a number of new roads.

Needless to say, the project, which launched in 1991, was incredibly expensive and encountered several delays. The final bill topped a staggering $14.8 billion once the project wrapped in 2007, which is $22.5 billion in today's money.

The Trans-Alaska Pipeline system was built between 1974 and 1977 at a cost of $8 billion, making it the world's largest privately funded project at that time. In today's dollars, that's around $41.7 billion.

Crucial to the Alaskan economy, the 800-mile-long pipeline has been instrumental in facilitating the growth of the state's oil industry.

Now discover the most expensive megaprojects in the world