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Critical infrastructure operators headquartered in Seattle

Tamtam tracks 37 critical infrastructure operators headquartered in Seattle. This list ranks all of them by number of employees on LinkedIn, led by Alaska Airlines, City of Seattle and Seattle Children's. Their median headcount is 942. Half of them were founded in 1949 or later.

๐Ÿ‡บ๐Ÿ‡ธ Seattle37 companiesUpdated Nov 2, 2026
#CompanyIndustryHeadquarters EmployeesFounded
1
Alaska Airlinesalaskaair.com

Passenger airline providing exceptional service through dedicated employees, focusing on safety, customer care, and community engagement.

Airlines and Aviation ๐Ÿ‡บ๐Ÿ‡ธ Seattle 13,396 n/a
2
City of Seattleseattle.gov

Providing diverse public services across multiple departments to support community well-being, infrastructure, and inclusive city development.

Government Administration ๐Ÿ‡บ๐Ÿ‡ธ Seattle 10,924 n/a
3
Seattle Children'sseattlechildrens.org

Providing compassionate pediatric care, conducting breakthrough research, and supporting families to ensure children receive hope, care, and cures.

Hospitals and Health Care ๐Ÿ‡บ๐Ÿ‡ธ Seattle 8,756 1907
4
Swedishprovidence.org

A powerful network of skilled physicians, care centers, research and treatments offering world-class care in the Puget Sound region

Hospitals and Health Care ๐Ÿ‡บ๐Ÿ‡ธ Seattle 8,501 n/a
5
Group Healthghc.org

Healthcare provider serving over 11 million members in eight states and DC, including 651,000 from Group Health Cooperative in Washington

Hospitals and Health Care ๐Ÿ‡บ๐Ÿ‡ธ Seattle 4,556 1947
6
UW Medicineuwmedicine.org

Integrated health system combining clinical care, research, and education to provide specialized and primary healthcare across multiple states.

Hospitals and Health Care ๐Ÿ‡บ๐Ÿ‡ธ Seattle 4,344 n/a
7
Harborview Medical Centeruwmedicine.org

Founded in 1877 as a six-bed hospital, now a leading academic medical center overlooking Puget Sound offering advanced medical care

Hospitals and Health Care ๐Ÿ‡บ๐Ÿ‡ธ Seattle 3,757 1877
8
University of Washington Medical Centeruwmedicine.org

A healthcare facility providing innovative, high-quality patient care with expanded services in oncology, radiology, and Neonatal Intensive Care

Hospitals and Health Care ๐Ÿ‡บ๐Ÿ‡ธ Seattle 3,167 1959
9
Port of Seattleportseattle.org

Ownership and operation of airport, fishing terminal, marinas, cruise and cargo terminals, real estate, supporting regional jobs and economic growth.

Government Administration ๐Ÿ‡บ๐Ÿ‡ธ Seattle 2,074 1911
10
Horizon Airhorizonair.jobs

A regional airline operating as the carrier of Alaska Airlines, with a fleet of Embraer 175 jet aircraft serving around 50 West Coast cities

Airlines and Aviation ๐Ÿ‡บ๐Ÿ‡ธ Seattle 2,074 1981
11
Sound Transitsoundtransit.org

Planning, building, operating regional transit systems to provide alternatives to traffic and accommodate population growth in Central Puget Sound.

Urban Transit Services ๐Ÿ‡บ๐Ÿ‡ธ Seattle 1,825 1996
12
Emeritusbrookdale.com

Providing senior living solutions and enriching lives through comfortable environments, nutritious meals, stimulating activities, and compassionate care, now part of Brookdaleยฎ Senior Living family

Hospitals and Health Care ๐Ÿ‡บ๐Ÿ‡ธ Seattle 1,822 1993
13
WaFd Bankwafdbank.com

A long-standing national bank dedicated to building healthy communities by providing straightforward banking solutions for clients since 1917

Banking ๐Ÿ‡บ๐Ÿ‡ธ Seattle 1,405 1917
14
Northwest Hospital & Medical Centeruwmedicine.org

A nonprofit community hospital offering comprehensive medical services, pioneering treatments, specialized cancer care, award-winning neurosciences programs, emergency services, and community health education

Hospitals and Health Care ๐Ÿ‡บ๐Ÿ‡ธ Seattle 1,300 1960
15
SSA Marinessamarine.com

Global logistics company founded in 1949, with operations on five continents, offering advanced facilities and transportation solutions to improve customer experience and accelerate global business growth

Transportation, Logistics, Supply Chain and Storage ๐Ÿ‡บ๐Ÿ‡ธ Seattle 1,250 1949
16
Seattle City Lightseattle.gov

This company is a large publicly owned utility providing affordable, reliable, and environmentally responsible power to homes and businesses in Seattle and surrounding areas

Utilities ๐Ÿ‡บ๐Ÿ‡ธ Seattle 1,187 1910
17
Sea Mar Community Health Centersseamar.org

A community-based organization providing quality health, housing, educational, and cultural services to diverse communities in Washington state

Hospitals and Health Care ๐Ÿ‡บ๐Ÿ‡ธ Seattle 1,174 1978
18
HomeStreet Bankhomestreet.com

A community bank offering a full range of financial services focused on building long-term relationships, supporting communities, and promoting housing

Financial Services ๐Ÿ‡บ๐Ÿ‡ธ Seattle 982 1921
19
The Polyclinicoptum.com

A leading independent multi-specialty clinic in the Puget Sound area, providing high-quality, personalized care with over 170 physicians

Hospitals and Health Care ๐Ÿ‡บ๐Ÿ‡ธ Seattle 942 1917
20
Bloodworks Northwestbloodworksnw.org

Nonprofit organization advancing transfusion medicine, patient care, and research in the Pacific Northwest through blood donations and tissue support

Hospitals and Health Care ๐Ÿ‡บ๐Ÿ‡ธ Seattle 926 1944
21
Public Health โ€“ Seattle & King Countykingcounty.gov

Hospital & health care company located in Seattle, WA, focusing on public health initiatives and services for the community

Hospitals and Health Care ๐Ÿ‡บ๐Ÿ‡ธ Seattle 873 n/a
22
Seattle Cancer Care Alliancefredhutch.org

merger of Fred Hutchinson Cancer Research Center and Seattle Cancer Care Alliance into Fred Hutchinson Cancer Center for cancer research and care

Hospitals and Health Care ๐Ÿ‡บ๐Ÿ‡ธ Seattle 782 2001
23
Pacific Medical Centerspacificmedicalcenters.org

Private, not-for-profit health care network in Puget Sound with 9 clinics, 175 providers, cutting-edge technology, and patient-focused care for diverse population

Hospitals and Health Care ๐Ÿ‡บ๐Ÿ‡ธ Seattle 694 n/a
24
Liberty Mutual Suretyโ„ขbusiness.libertymutual.com

A global provider of surety and guarantee solutions for construction companies and corporations, operating in over 60 countries with strong financial credit ratings

Insurance ๐Ÿ‡บ๐Ÿ‡ธ Seattle 656 n/a
25
Seattle Public Utilitiesseattle.gov

The company partners with the community to manage water and waste resources equitably, promoting a healthy environment and economy for future generations

Government Administration ๐Ÿ‡บ๐Ÿ‡ธ Seattle 625 n/a
26
Foss Maritime Companyfoss.com

This company provides marine transportation and logistics services, offering safe and innovative solutions for transportation challenges and harbor jobs worldwide

Transportation, Logistics, Supply Chain and Storage ๐Ÿ‡บ๐Ÿ‡ธ Seattle 555 1889
27
King County Department of Natural Resources and Parkskingcounty.gov

The company works to support sustainable communities and protect the environment through regional parks, water protection, waste management, and environmental stewardship

Utilities ๐Ÿ‡บ๐Ÿ‡ธ Seattle 516 1958
28
Neighborcare Healthneighborcare.org

Providing comprehensive primary medical, dental, and mental health care services to underserved communities in the Seattle area without turning anyone away

Hospitals and Health Care ๐Ÿ‡บ๐Ÿ‡ธ Seattle 509 1968
29
Centerline Logistics Corporationcenterlinelogistics.com

A leading provider of marine transportation services on the West Coast, New York Harbor, and the US Gulf Coast, specializing in petroleum products, ship assist, and general cargo services

Maritime Transportation ๐Ÿ‡บ๐Ÿ‡ธ Seattle 432 1987
30
King County Sheriff's Officekingcounty.gov

Providing public safety services to 500,000 community members in unincorporated King County and sixteen contract-city and transit partners

Public Safety ๐Ÿ‡บ๐Ÿ‡ธ Seattle 371 1852
31
Seattle Department of Transportationseattle.gov

A leading municipal transportation agency in Seattle, dedicated to creating an equitable, sustainable, and vibrant city through maintenance, operations, and expansion of transportation networks

Government Administration ๐Ÿ‡บ๐Ÿ‡ธ Seattle 348 1996
32
Lyndenlynden.com

The company offers transportation and logistics solutions in various regions, including Alaska and Canada, allowing customers to ship via air, land, or sea

Transportation, Logistics, Supply Chain and Storage ๐Ÿ‡บ๐Ÿ‡ธ Seattle 299 1906
33
Northland Communicationsvyvebroadband.com

A leading technology provider offering advanced fiber optic services and solutions with a focus on innovation, customer service, and community support

Telecommunications ๐Ÿ‡บ๐Ÿ‡ธ Seattle 212 1981
34
Ceres Terminalsssamarine.com

A global enterprise with over 260 locations worldwide, specializing in cargo handling operations and providing technologically advanced facilities for efficient commerce movement

Truck Transportation ๐Ÿ‡บ๐Ÿ‡ธ Seattle 185 1949
35
Lynden Transportlynden.com

A multi-mode carrier in Alaska since 1954, offering scheduled road service, barge and ship transport across the state and globally

Truck Transportation ๐Ÿ‡บ๐Ÿ‡ธ Seattle 182 n/a
36
Summit Power Groupsummitpower.com

Project development company specializing in high-efficiency natural gas, carbon capture, and utility-scale solar and wind power projects with extensive experience in the energy industry

Oil and Gas ๐Ÿ‡บ๐Ÿ‡ธ Seattle 77 n/a
37
Fortune Bankfortunebankwa.com

The company offers personalized banking services for individuals and businesses, with a dedicated team, local decision-making, and a strong capital base

Banking ๐Ÿ‡บ๐Ÿ‡ธ Seattle 14 2006

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How this list is built

Every company on this list has a Tamtam company profile. The industry is the one the company gives on LinkedIn; categories such as SaaS or fintech are classified by Tamtam's AI from the company's website and LinkedIn page; and the headquarters city must match the company's own address. Companies are ranked by the number of employees on LinkedIn, and the list is refreshed every night. Classifications can be wrong, so treat the list as a starting point rather than an official ranking. Last updated Nov 2, 2026.

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