| # | Company | Employees |
|---|---|---|
| 1 |
Nalco Water, An Ecolab Companyecolab.com
A global leader in water and process management solutions, leveraging connected chemistry and digital innovation to optimize sustainability and business outcomes |
12,751 |
| 2 |
KeHE Distributorskehe.com
A mission-driven distributor of natural, organic, specialty, and fresh products with a large employee-owner network across North America |
4,529 |
| 3 |
Edward Hospitalendeavorhealth.org
United healthcare system focused on personal patient experiences, convenient access to world-class care, serving communities with hospitals and clinics. |
4,168 |
| 4 | 3,096 | |
| 5 |
Nicor Gasnicorgas.com
Leading natural gas distribution company in Illinois, ensuring safe and reliable gas delivery to over 22 million homes and businesses Committed to community, safety, and environmental stewardship |
1,521 |
| 6 |
Royal Cyber Inc.royalcyber.com
Empowering enterprises to evolve with agility, security, and innovation through digital transformation and modernization of legacy systems with AI-driven solutions. |
1,383 |
| 7 |
Naperville Community Unit School District 203naperville203.org
The company focuses on educating students to be self-directed learners, collaborative workers, complex thinkers, quality producers, and community contributors |
1,379 |
| 8 |
North Central Collegenorthcentralcollege.edu
A college in Illinois offering a wide range of undergraduate and graduate programs, known for its top-notch facilities and programs |
1,374 |
| 9 |
Five-Star AudioVisualfive-starav.com
Luxury audiovisual solutions provider for the hospitality industry, specializing in innovative technology, high service standards, and immersive experiences |
1,318 |
| 10 |
Eby-Brown Company, LLCeby-brown.com
Leading convenience store supplier delivering innovative foodservice, merchandising, technology, and insight to 10,000+ C-store retailers across North America as part of PFG family |
1,093 |
| 11 |
Impact Advisorsimpact-advisors.com
Healthcare management consulting firm solving industry challenges with team of experts, quality solutions, and measurable value Award-winning and innovative culture |
927 |
| 12 |
Bella Baby Photographybellababyphotography.com
Professional photographers capture natural, artistic moments of newborns and families in hospitals, using natural light and a photojournalistic style approach |
669 |
| 13 |
City of Napervillenaperville.il.us
The company is located in Naperville, offering a variety of amenities such as top schools, a great library system, parks, and healthcare providers in a low-crime environment |
616 |
| 14 |
Cultivate Behavioral Health & Educationcultivatebhe.com
Utilizing evidence-based strategies, Cultivate provides engaging and dynamic Applied Behavior Analysis services tailored to each child for meaningful change |
615 |
| 15 |
CoreFlex Solutions Inc.coreflexsolutions.com
The company specializes in digital transformation services, utilizing Salesforce, software engineering, cloud, mobility, AI/ML, IoT, data analytics, and end-to-end managed services for various industries |
537 |
| 16 |
Wilton Brandswilton.com
Innovative company passionate about baking and decorating, delivering products and ideas that evolve with trends, backed by a multi-billion-dollar, family-owned parent company |
528 |
| 17 |
Calamos Investmentscalamos.com
Diversified global asset and wealth management firm offering innovative investment strategies across multiple asset classes and client types. |
475 |
| 18 |
Sourcebookssourcebooks.com
Independent, women-led publisher since 1987 changing lives through wide range of genres, committed to driving results and creating a vibrant future for books |
474 |
| 19 |
Oncourse Home Solutionsoncoursehome.com
A company offering affordable protection for service line problems, managing over 17 million contracts nationwide with hassle-free repairs and exceptional customer service |
449 |
| 20 |
General Employment Enterprisesgeegroupcareers.com
Specialized staffing solutions provider offering professional staffing in IT, engineering, finance, and healthcare sectors, as well as light industrial staffing services |
375 |
| 21 |
Doctors of Physical Therapydoctorsofphysicaltherapy.com
A therapist-owned company providing high-quality care with doctorate-level therapists for continuity, quality, and evidence-based treatment, including on-site rehab clinics |
373 |
| 22 |
Calvary Church of Napervillecalvarynaperville.org
A multi-cultural church providing a space to discover and apply Biblical truths, connect with others, and experience life with Jesus Christ |
347 |
| 23 |
Endeavor Health Behavioral Healtheehealth.org
Behavioral health services offering inpatient and outpatient care, medication management, therapy, and treatment for various disorders such as anxiety, depression, and eating disorders |
339 |
| 24 |
Profood International Incprofoodinternational.com
A food additive distributor offering high-quality products like vitamins, organic acids, preservatives, amino acids, enzymes, prebiotics, sweeteners, proteins, dietary fibers, and more Operating in US and Asia |
339 |
| 25 |
Stiversstivers.com
Staffing and recruiting specializing in office, professional, supply chain, and retail merchandising positions, creating relationships through personalized approaches since 1945 |
337 |
| 26 |
Chervon North America, Incglobal.chervongroup.com
Global provider in power tools and outdoor equipment industries, focusing on innovation and collaboration across manufacturing, design, and sales offices worldwide |
322 |
| 27 |
Naperville Park Districtnapervilleparks.org
Established in 1966, this independent municipal agency manages over 2,500 acres with 150+ parks and facilities, offering 900+ recreational programs and events annually |
311 |
| 28 |
Dealer Inspiredealerinspire.com
A leading automotive platform provider focused on developing innovative technologies for dealers and consumers, promoting collaboration and giving back to communities |
302 |
| 29 |
Evolutyz Corpevolutyz.com
An award-winning IT consulting firm providing custom technical solutions to transform businesses and empower IT experts to reach their full potential |
194 |
| 30 |
Illinois Health and Hospital Associationteam-iha.org
Advocating for Illinois hospitals and health systems to provide high-quality healthcare access and services for all communities across the state |
193 |
| 31 |
Agami Technologiesagamitechnologies.com
A software development organization focusing on desktop, web, and mobile applications, cloud computing, and equality with a diverse team |
180 |
| 32 | 175 | |
| 33 |
Contruentcontruent.com
Premier capital project management software empowering owners and EPCs to build construction projects faster with integrated cost and scheduling solutions |
174 |
| 34 |
Infogix, Inc. (now Precisely)precisely.com
This company offers data integrity software to ensure accurate and reliable data, enabling informed business decisions and digital transformation |
173 |
| 35 |
ennVee TechnoGroup Incennvee.com
A leading IT solution provider offering performance management tools and services for Oracle, SAP, NetSuite, automation, digital transformation, and cloud infrastructure |
169 |
| 36 |
Neuqua Valley High Schoolipsd.org
Comprehensive four-year high school in Indian Prairie School District #204, established in 1997 with first graduation class in 2000 |
162 |
| 37 |
INSTEC (an Insurity company)insurity.com
A leading provider of property and casualty insurance software and data analytics, serving top insurers, brokers, and MGAs worldwide Delivering simplified insurance experiences |
162 |
| 38 |
Meadowbrook Rehabilitationmeadowbrookrehabilitation.com
Skilled nursing facilities in Chicagoland, Illinois providing person-centered care, customized healthcare plans, and a range of in-house care services for residents |
158 |
| 39 |
Libsys Inclibsysinc.com
A Chicago-based technology-focused organization specializing in delivering end-to-end IT solutions with a customer-centric approach, leveraging internet technologies for business competitiveness |
156 |
| 40 |
DHJJ Certified Public Accountants and Business Advisorsdhjj.com
A multifaceted business advisory firm in Chicagoland with over 100 associates offering CPA, tax, assurance services, specialty services, and financial advisory |
153 |
| 41 |
ampliFI Loyalty Solutionsamplifiloyalty.com
Industry-leading provider of custom loyalty and engagement programs for financial institutions, offering data-driven rewards, real-time rewards, unique earning opportunities, and dedicated support |
152 |
| 42 |
Naperville Public Librarynaperville-lib.org
A community-focused public library in Naperville, serving residents with three facilities, receiving high ratings and recognition for excellence in service |
151 |
| 43 |
Charles Rutenberg Realty of Illinoismycrr.com
The company focuses on empowering real estate agents by allowing them to retain majority of their commissions and providing necessary support |
150 |
| 44 |
Monarch Landingwelcometomonarchlanding.com
Senior living community offering a variety of career opportunities in healthcare, activities, management, and more Committed to providing quality care and benefits to employees |
147 |
| 45 |
Delta Dental of Illinoisdeltadentalil.com
A trusted partner in dental benefits, promoting overall health and well-being through customer-focused products, cost-saving strategies, and community health programs |
142 |
| 46 |
Sound Incorporatedsoundinc.com
A technology solutions provider specializing in critical communications, healthcare solutions, security, network solutions, AV systems, and professional services for various industries |
89 |
| 47 |
Calamos Wealth Managementwm.calamos.com
Wealth management firm providing comprehensive financial planning, investment management, estate and tax planning, and business transition services to individuals, families, and foundations |
62 |
| 48 |
UMT Globalumtglobal.com
A logistics company based in Naperville, Illinois, focused on innovation and technology to provide exceptional and reliable logistical operations |
60 |
| 49 |
Outsource Solutions Grouposgusa.com
A full service IT development and maintenance company in Chicagoland area, offering networking, cloud-based solutions, and competitive pricing on hardware/software |
56 |
| 50 |
JBS Logistics & Warehousingkochlogistics.com
Provider of food-grade warehousing, cross-dock operations, trucking services (TL, LTL, expedited), and brokerage solutions for US shippers, with international logistics capabilities |
47 |
| 51 |
Berkley Program Specialists (a Berkley Company)berkley-ps.com
A leading insurance operation specializing in program business, providing access to top carriers, program management expertise, and reinsurance support for casualty-driven programs |
44 |
| 52 |
CloudNurocloudnuro.ai
Next-gen SaaS company utilizing AI & ML for optimizing SaaS operations, managing spend, enhancing security/compliance, and maximizing ROI for investments |
43 |
| 53 |
Talented IT, Inc.talentedit.com
A global IT consulting firm focused on breakthrough performance through intelligent technology use, with skilled professionals committed to client satisfaction |
43 |
| 54 |
HaleMind Inc.halemind.com
Chicago-based healthcare technology startup focused on promoting personal engagement for a healthy life Facilitates data sharing between individuals and healthcare providers for better patient outcomes |
28 |
| 55 |
Napco Brandsnapcobrands.com
A family-owned coffee roastery with over 120 years of experience, offering premium coffee brands, private label services, and tailored solutions for diverse clientele |
26 |
| 56 |
AuctusSolauctussol.com
Global provider of professional services and business enterprise solutions for over 25 years, specializing in Digital Transformation, SAP, Cybersecurity, Data Engineering, and Consulting |
26 |
| 57 |
EGO POWER+egopowerplus.com
Innovative company offering cordless outdoor power equipment powered by a 56-volt Lithium Ion battery for gas-like performance without the noise and fumes |
26 |
| 58 |
Solution Partners Servicessolpartservices.com
Solution Partners Services provides comprehensive IT services for various clients, delivering marketplace or customized solutions with an emphasis on proactive delivery and quality assurance |
24 |
| 59 |
Target Decorated Appareltargetda.com
A nationally recognized apparel decorator offering unique decorating techniques for screen-printed and embroidered apparel, alongside packaging and fulfillment services |
23 |
| 60 |
Trans Lines Inc.translinesinc.com
A transportation company based in Illinois, specializing in strategic shipping solutions with a team of drivers and office members dedicated to prioritizing every shipment |
18 |
| 61 |
Sage Tree, LLCadvantageunifiedcommerce.com
Specializing in e-commerce and brand strategy, sales management, content creation, advertising, and marketplace management to help brands succeed online and offline |
18 |
| 62 |
Partners Wealth Managementpartnerswealth.com
An independent wealth services firm offering comprehensive planning, investment, and risk management services to affluent families, institutions, and businesses |
13 |
| 63 |
ERMLabs Incermlabs.com
Innovative cloud solutions company offering app development, consulting, and services for various platforms to drive business objectives and increase productivity |
11 |
| 64 |
TecForcetecforce.com
A technology company providing top-tier solutions to help businesses innovate, accelerate time to market, and reimagine their products for a digital-first world |
11 |
| 65 |
The Kitchen Masterthekitchenmaster.com
A top design-build firm specializing in cutting-edge kitchen and bathroom remodeling Trust our certified designers and skilled craftsmen for your dream space |
10 |
| 66 |
Basin Logisticsbasinlogistics.com
An international third party logistics organization based in Naperville, IL, providing best-in-class services like truckload, intermodal, rail, air, and ocean transportation solutions |
9 |
| 67 |
Sharpedge Solutions Incesharpedge.com
Global IT Solutions firm specializing in Business Integration, Business Process Management, and Service-Oriented Architecture for various corporate clients in multiple industries |
9 |
| 68 |
Harter Investment Strategieshis.biz
Investment firm supporting entrepreneurial dreams by fueling passion and igniting business growth, helping bring visions to life and reach new heights |
8 |
| 69 |
Erthe Energy Solutionsertheenergysolutions.com
A woman-owned business with 35 years' experience in energy efficiency, specializing in helping utilities improve program portfolio operations and customer experience |
7 |
| 70 |
West Suburban Angels Inc.westsuburbanangels.com
An angel investment group that provides financial support and guidance to startups and early-stage companies looking to grow and scale |
7 |
| 71 |
Digimite Technologymydigimite.com
A global managed services provider supporting medium to large businesses with IT infrastructure and strategy, ensuring world class customer value |
4 |
| 72 |
Hagen Global Consulting LLChagenglobal.com
A global leader in innovative energy solutions, specializing in project reviews, due diligence, engineering assessments, and tackling unique challenges in the industry |
4 |
| 73 |
Outsource IT Solutions Group, Inc.osgusa.com
A Naperville-based company offering outsourced IT services to businesses in the Chicago area, specializing in network information technology solutions |
3 |
| 74 |
PackDashpackdash.com
Supply chain solutions company specializing in multi-channel fulfillment services for ambitious consumer brands, offering 2-day shipping, inventory management, and kitting services |
3 |
| 75 |
Plastic Processing Solutionsplasticprocessingsolutions.net
Specializing in plastic processing solutions, the company offers turn-key solutions including machinery, engineering, integration, and mechanical services |
3 |
| 76 |
Viz Pointviz-point.com
A 3rd Party Logistics Company offering tailored supply chain services to businesses seeking growth or cost reduction through innovative freight programs and technology |
3 |
| 77 |
Refreshing Renovationsrefreshingrenovations.net
A home repair and renovation company specializing in interior and exterior renovations, flooring, pest exclusion, and general handyman services in various suburban areas |
2 |
| 78 |
Hema Transportation
The company specializes in transportation and logistics services, ensuring efficient and reliable movement of goods from one location to another |
2 |
Turn this list into pipeline
Tamtam finds the decision-makers at every company on a list like this one, with verified emails, phone numbers and the buying signals that tell you when to reach out.
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