The 25 largest companies in Oak Ridge (2026 list)

#	Company	Industry	Headquarters	Employees	Founded
1	Oak Ridge National Laboratory ornl.gov Conducts scientific research and development to advance energy availability, environmental protection, national security, and technological innovation for the Department of Energy.	Research Services	🇺🇸 Oak Ridge	6,512	1943
2	Y-12 National Security Complex y12.doe.gov Specializes in manufacturing components, subassemblies, and quality evaluations for US nuclear deterrence, weapons threat reduction, naval reactors, and national security solutions	Defense and Space Manufacturing	🇺🇸 Oak Ridge	2,242	1943
3	ORAU orau.org Innovative scientific and technical solutions for research, education, public health, environmental protection, and national security, while working with federal and commercial customers	Government Administration	🇺🇸 Oak Ridge	865	1946
4	UCOR ucor.com Leader in deactivating and demolishing nuclear facilities, committed to safe performance, innovation, and environmental protection in partnership with DOE	Environmental Services	🇺🇸 Oak Ridge	743	2011
5	ORNL Federal Credit Union ornlfcu.com A financial cooperative serving Central East Tennessee, helping members save, decrease debt, and plan for the future with federally insured accounts	Banking	🇺🇸 Oak Ridge	634	1948
6	Oak Ridge Schools ortn.edu A school district in Oak Ridge, TN with PreK-12 schools emphasizing equity, diversity, and equal employment opportunities for students and staff	Education Administration Programs	🇺🇸 Oak Ridge	569	1943
7	Actor \| Freelance linkedin.com A professional actor offering services on a freelance basis for various projects Bringing creativity and talent to the entertainment industry	Performing Arts	🇺🇸 Oak Ridge	515	n/a
8	RSI rsienv.com A group of companies providing environmental, nuclear, construction management, and professional services for cleanup initiatives nationwide, focusing on protecting and restoring sites	Environmental Services	🇺🇸 Oak Ridge	512	1996
9	Navarro Research and Engineering navarro-inc.com A federal contractor specializing in overcoming environmental challenges in the nuclear and environmental industries for various government agencies nationwide	Environmental Services	🇺🇸 Oak Ridge	504	1993
10	Lakeland Bank provident.bank A leading financial institution offering a wide range of commercial and consumer banking services, recognized for financial strength, quality service, and community involvement	Banking	🇺🇸 Oak Ridge	412	1969
11	Oak Ridge Institute for Science and Education orise.orau.gov A nonprofit contractor supporting the US Department of Energy by providing expertise in STEM workforce development, scientific reviews, and environmental evaluations	Government Administration	🇺🇸 Oak Ridge	349	1992
12	Bechtel Jacobs bechteljacobs.com Environmental management contractor for US Department of Energy's Oak Ridge Office, specializing in cleanup, waste management, and reindustrialization programs at Oak Ridge Reservation	Environmental Services	🇺🇸 Oak Ridge	349	1998
13	Edgewater Technical Associates, LLC edgewatertech.net Provider of professional and technical services in nuclear and hazardous operations, supporting government agencies and commercial nuclear industry across US and Canada	Facilities Services	🇺🇸 Oak Ridge	308	2003
14	Lockeed Martin onlinecareer360.com A construction company based in Oak Ridge, Tennessee, specializing in various projects and services within the United States	Construction	🇺🇸 Oak Ridge	270	n/a
15	Appalachian Underwriters, Inc.appund.com A leading insurance wholesale brokerage specializing in Workers' Compensation, Commercial Specialty, and Personal Lines products, with nationwide coverage and a wide range of high-quality options	Insurance	🇺🇸 Oak Ridge	264	1996
16	Methodist Medical Center of Oak Ridge covenanthealth.com Religious institution located in Oak Ridge, Tennessee providing medical services and care to the community	Hospitals and Health Care	🇺🇸 Oak Ridge	255	1943
17	Bristol Bay Construction Holdings LLC bbch-llc.com A platform for multiple subsidiaries offering general construction, restoration, energy infrastructure, environmental services, and professional support with a focus on quality and consistency	Construction	🇺🇸 Oak Ridge	246	1992
18	Spectra Tech, Inc.spectratechinc.com Provider of high-quality engineering, environmental, and nuclear services, specializing in technical solutions for government and commercial clients worldwide since 1995	Environmental Services	🇺🇸 Oak Ridge	169	1995
19	Emory Valley Center emoryvalleycenter.org Provider of services for individuals with disabilities in East Tennessee, including behavioral health, community support, education, technology, family support, and workforce development	Individual and Family Services	🇺🇸 Oak Ridge	157	1955
20	Ridgeview Behavioral Health Services ridgeview.com A private, not-for-profit community mental health center in East Tennessee providing services in multiple locations, focused on hope, healing, and recovery for clients	Mental Health Care	🇺🇸 Oak Ridge	152	1957
21	Omega Technical Services omegatechserv.com Omega Technical Services provides expert technical and scientific talent to governmental and commercial clients, specializing in safe nuclear operations and compliance	Defense and Space Manufacturing	🇺🇸 Oak Ridge	150	1995
22	Esco Optics, Inc.escooptics.com A family-owned optic manufacturer in the US, specializing in standard catalog optics, precision components, and ITAR optics with exceptional customer service and quality	Industrial Machinery Manufacturing	🇺🇸 Oak Ridge	22	1955
23	Crossridge Precision Inc crossridgeprecision.com A precision machining and assembly company specializing in aerospace, automotive, heavy truck, and industrial products, committed to exceeding customer expectations	Aviation and Aerospace Component Manufacturing	🇺🇸 Oak Ridge	20	1962
24	Oak Ridge Tool-Engineering, Inc.ortool.com A full-service precision engineering company offering tooling, machining, fabrication, and manufacturing services to diverse industries worldwide with top quality and efficiency	Mechanical Or Industrial Engineering	🇺🇸 Oak Ridge	18	1962
25	3DOLOGiE 3dologie.com Specializing in advanced manufacturing technology, this company offers solutions with top 3D printer brands and provides 3D printing services in the Southeastern United States	Industrial Machinery Manufacturing	🇺🇸 Oak Ridge	3	2018

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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 Oct 24, 2026.

The same list elsewhere in United States

The largest companies in the United States 91,669
The largest companies in California 12,813
The largest companies in New York State 10,485
The largest companies in Texas 8,086
The largest companies in Florida 4,945
The largest companies in Illinois 4,175
The largest companies in Pennsylvania 3,110
The largest companies in Massachusetts 3,093
The largest companies in Georgia 2,632
The largest companies in Ohio 2,618
The largest companies in New Jersey 2,569
The largest companies in Virginia 2,503
The largest companies in Michigan 2,346
The largest companies in North Carolina 2,174
The largest companies in Alabama 1,806
The largest companies in Washington State 1,785
The largest companies in Colorado 1,774
The largest companies in Minnesota 1,700
The largest companies in Maryland 1,527
The largest companies in Wisconsin 1,482
The largest companies in New York 6,920
The largest companies in San Francisco 2,030
The largest companies in Houston 1,791
The largest companies in Chicago 1,668