List of Seattle megaprojects
This is a list of megaprojects in the Seattle area. For this list, a megaproject follows the often cited definition of $1 billion or more.
| Name | Type | Status | Cost | Notes |
| Sound Transit 3 | Transit | $54 billion | Divided between several projects, to open between 2024 and 2041 | |
| Vancouver B.C.–Seattle–Portland high-speed railway | Transit | Initiative of the Pacific Coast Collaborative between state and provincial governments | ||
| State Route 520 bridge replacement and corridor program | Road | $4.56 billion | New bridge opened in April 2016, rest of corridor anticipated to be complete by 2029 | |
| Alaskan Way Viaduct replacement tunnel | Road tunnel | $4.25 billion | ||
| Amazon headquarters, Seattle | Office buildings | $4 billion | ||
| East Link Extension | Transit line | $3.7 billion | Scheduled to open in 2023 | |
| Lynnwood Link Extension | Transit line | $2.9 billion | Scheduled to open in 2024 | |
| Interstate 405 improvements | Road | 2003 Nickel and 2005 Transportation Partnership Account: $1.5 billion; 2015 Connecting Washington package: $1.3 billion | ||
| Central Link, Seattle and Tukwila | Transit line | $2.44 billion | ||
| Spring District, Bellevue | Urban development | $2.3 billion | Scheduled to open in phases from 2017 to 2023 | |
| Puget Sound Gateway | Road | $1.989 billion | ||
| Northgate Link Extension | Transit tunnel | $1.9 billion | Scheduled to open in 2021 | |
| Brightwater Tunnel | Sanitation infrastructure | $1.8 billion | First billion-dollar tunnel in Seattle | |
| University Link tunnel | Transit tunnel | $1.7 billion | Completed $200 million under budget. Central Link light rail service began in 2016. | |
| Interstate 5 HOV lanes in Tacoma and Fife | Road expansion | $1.6 billion | Scheduled to be complete in 2022 | |
| Yesler Terrace redevelopment | Urban development | $1.5 billion | May increase to $1.7 billion | |
| Lincoln Square expansion, Bellevue | Urban development | $1.2 billion | ||
| Seattle–Tacoma International Airport third runway | Airport infrastructure | $1.1 billion | Does not include $200 million in soundproofing for schools | |
| Seattle seawall replacement | Shoreline infrastructure | $1.07 billion | ||
| Mount Baker Tunnel | Road tunnel | Earliest billion-dollar project on this list | ||
| Point Ruston | Urban development | $1 billion | ||
| Snoqualmie Ridge | Master-planned community | $1 billion | Made suburb of Snoqualmie the fastest growing city in Washington | |
| Hewitt Avenue Trestle replacement | Road bridge | |||
| Puget Sound salmon recovery–culvert replacement | Stream restoration | $3.7 billion | Began in 1991, expanded by June 2018 U.S. Supreme ruling in favor of tribal fisheries rights. Projected to continue through 2030. |
Other Washington state megaprojects
Notable Washington state megaprojects outside the immediate Seattle area include the following:- Hanford cleanup $113.6 billion
- *Hanford Vitrification Plant $12 to $16.8 billion
- WNP-3 and WNP-5 nuclear power plants up to $24 billion estimated to complete
- Grand Coulee Dam $5.541 billion in 2017 dollars
- *Third Powerplant $2.002 billion in 2017 dollars
- North Spokane Corridor : $1.49 billion
- Lower Snake River Wind Project phase I and II $1.33 billion
- Interstate 90 widening near Snoqualmie Pass: $1 billion