# 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 $1billion (2017 dollars) or more.
| Name | Type | Status | Cost | Notes |
| Sound Transit 3 | Transit | In progress | $54 billion | Divided between several projects, to open between 2024 and 2041 |
| Vancouver B.C.–Seattle–Portland high-speed railway | Transit | Proposed | $24–$42 billion | Initiative of the Pacific Coast Collaborative between state and provincial governments |
| State Route 520 bridge replacement and corridor program | Road | In progress | $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 | Completed in 2019 | $4.25 billion (2009 est.) | |
| Amazon headquarters, Seattle | Office buildings | In progress | $4 billion | |
| East Link Extension | Transit line | In progress | $3.7 billion | Scheduled to open in 2023 |
| Lynnwood Link Extension | Transit line | In progress | $2.9 billion | Scheduled to open in 2024 |
| Interstate 405 (Eastside) improvements | Road | In progress | More than $2.8 billion | 2003 Nickel and 2005 Transportation Partnership Account: $1.5 billion; 2015 Connecting Washington package: $1.3 billion |
| Central Link, Seattle and Tukwila | Transit line | Completed in 2009 | $2.44 billion | |
| Spring District, Bellevue | Urban development | In progress | $2.3 billion | Scheduled to open in phases from 2017 to 2026 |
| Puget Sound Gateway (SR 167 and SR 509) | Road | In progress | $1.989 billion | |
| Northgate Link tunnel | Transit tunnel | Completed in 2021 | $1.9 billion | |
| Brightwater Tunnel | Sanitation infrastructure | Completed in 2011 | $1.8 billion | First billion-dollar tunnel in Seattle |
| University Link tunnel | Transit tunnel | Completed in 2012 | $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 | In progress | $1.6 billion | Scheduled to be complete in 2022 |
| Yesler Terrace redevelopment | Urban development | In progress | $1.5 billion | May increase to $1.7 billion |
| Lincoln Square expansion, Bellevue | Urban development | Completed in late 2017 | $1.2 billion | |
| Seattle–Tacoma International Airport third runway | Airport infrastructure | Completed in 2008 | $1.1 billion | Does not include $200 million in soundproofing for schools |
| Seattle seawall replacement | Shoreline infrastructure | Completed in 2017 | $1.07 billion (2014 estimate) | |
| Mount Baker Tunnel | Road tunnel | Completed in 1986 | Over $1 billion | Earliest billion-dollar project on this list |
| Point Ruston | Urban development | In progress | $1 billion | |
| Snoqualmie Ridge | Master-planned community | Completed in 2018 | $1 billion | Made suburb of Snoqualmie the fastest growing city in Washington (2010) |
| Hewitt Avenue Trestle replacement (U.S. Route 2, Everett) | Road bridge | Proposed | $620 million to $2 billion | |
| Puget Sound salmon recovery–culvert replacement | Stream restoration | In progress | $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 (cancelled, WPPSS default)
* Grand Coulee Dam $5.541 billion in 2017 dollars
** Third Powerplant (completed 1980) $2.002 billion in 2017 dollars
* North Spokane Corridor (freeway): $1.49 billion
* Lower Snake River Wind Project phase I and II (Tucannon River Wind Farm) $1.33 billion
* Interstate 90 widening near Snoqualmie Pass: $1 billion