Company lists · Data refreshed September 2026

Top 25 Environmental consulting companies based in the United States

Name: Environmental consulting companies based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 19, 2026 6,096 companies tracked

RevenueBase identified 6,096 company matches for environmental consulting companies associated with the United States as of September 2026 and tracks 187,066 professional contacts across them, including 88,013 with verified work emails. Houston is the largest hub.

This list covers company matches for environmental consulting companies associated with the United States, found by RevenueBase SmartSearch using the meaning of business descriptions in its company graph at Exact. Ranked by professionals tracked, largest first. Rows show recorded descriptions where available, Exact search membership and the snapshot date. Data refreshed September 19, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase SmartSearch, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list RevenueBase SmartSearch · Exact Recorded Sep 19, 2026 How this list was built

6,096Companies

187,066Contacts tracked

88,013Verified emails

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The 25 largest environmental consulting companies based in the United States

Ranked by team size

Top 25 of 6,096 company matches for environmental consulting companies based in the United States, ordered by professional contacts tracked in RevenueBase, largest first. Recorded Sep 19, 2026. The RevenueBase SmartSearch column shows Exact match membership in this saved search. Click a contact count to view that company's people. Totals use company locations recorded by RevenueBase; the displayed preview is a smaller selection.
#	Company	RevenueBase SmartSearch	Headquarters	Employees	Contacts
1	Tetra Tech	Exact match	Pasadena, CA, United StatesHQ recorded Sep 19, 2026	10001+	12,999 contacts →
	Exact match “Tetra Tech is the leader in water, environment and sustainable infrastructure, providing high-end technical and engineering services for projects worldwide.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
2	WSP In The U.S	Exact match	New York, NY, United StatesHQ recorded Sep 19, 2026	10001+	9,318 contacts →
	Exact match “What if you could shape built and natural environments – and the future of those that use them?” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
3	Terracon	Exact match	Olathe, KS, United StatesHQ recorded Sep 19, 2026	5,001-10,000	6,113 contacts →
	Exact match “Terracon is a 100 percent employee-owned consulting engineering firm providing quality services to clients.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
4	APTIM	Exact match	Baton Rouge, LA, United StatesHQ recorded Sep 19, 2026	1,001-5,000	2,639 contacts →
	Exact match “APTIM enhances the quality of the environment, wellbeing of people, resilience of communities, and opportunity for employees to make a difference, not just a living.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
5	Brown And Caldwell	Exact match	Walnut Creek, CA, United StatesHQ recorded Sep 19, 2026	1,001-5,000	2,473 contacts →
	Exact match “Headquartered in Walnut Creek, Calif, Brown and Caldwell is an employee-owned firm with 2,100+ professionals serving clients locally and globally from 52 locations.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
6	Geosyntec Consultants	Exact match	Boca Raton, FL, United StatesHQ recorded Sep 19, 2026	1,001-5,000	2,393 contacts →
	Exact match “Geosyntec is a consulting and engineering firm that works with private and public sector clients to address new ventures and complex problems involving our environment, natural…” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
7	Providence	Exact match	Baton Rouge, LA, United StatesHQ recorded Sep 19, 2026	n/a	2,232 contacts →
	Exact match “Providence is an employee-owned engineering and environmental consulting firm.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
8	ECS Group Of Companies	Exact match	Chantilly, VA, United StatesHQ recorded Sep 19, 2026	1,001-5,000	2,210 contacts →
	Exact match “ECS Group of Companies is a Chantilly, VA-based consulting engineering firm.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
9	Langan Engineering & Environmental Services	Exact match	Parsippany, NJ, United StatesHQ recorded Sep 19, 2026	1,001-5,000	2,177 contacts →
	Exact match “Langan's client-focused, highly entrepreneurial culture cultivates an environment of opportunities in which career growth and teamwork flourish.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
10	Civil & Environmental Consultants, INC	Exact match	Moon Township, PA, United StatesHQ recorded Sep 19, 2026	1,001-5,000	2,145 contacts →
	Exact match “Civil & Environmental Consultants, Inc.(CEC) provides comprehensive market-oriented consulting services that advance the strategic business objectives of its clients.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
11	Hazen And Sawyer	Exact match	New York, NY, United StatesHQ recorded Sep 19, 2026	1,001-5,000	2,100 contacts →
	Exact match “As Hazen marks 75 years, we celebrate a legacy of absolute commitment to our clients while delivering the best technical work available anywhere.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
12	LJA	Exact match	Houston, TX, United StatesHQ recorded Sep 19, 2026	1,001-5,000	1,932 contacts →
	Exact match “Employee-Owned.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
13	Swca Environmental Consultants	Exact match	Phoenix, AZ, United StatesHQ recorded Sep 19, 2026	1,001-5,000	1,629 contacts →
	Exact match “Founded on a commitment to sound science and creative solutions, SWCA is a leader in environmental and management consulting services.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
14	GEI Consultants, INC	Exact match	Woburn, MA, United StatesHQ recorded Sep 19, 2026	1,001-5,000	1,604 contacts →
	Exact match Recorded description not available. Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
15	Exponent	Exact match	Menlo Park, CA, United StatesHQ recorded Sep 19, 2026	1,001-5,000	1,560 contacts →
	Exact match “In an era of accelerating change, Exponent is the only premium engineering and scientific consulting firm with the depth and breadth of expertise to solve our clients’ most…” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
16	Montrose Environmental Group	Exact match	Little Rock, AR, United StatesHQ recorded Sep 19, 2026	1,001-5,000	1,529 contacts →
	Exact match “Onterris (formerly Montrose Environmental Group) was one of the first to see environmental responsibility as not just an imperative but as a strategic asset.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
17	Weston Solutions, INC	Exact match	West Chester, PA, United StatesHQ recorded Sep 19, 2026	1,001-5,000	1,441 contacts →
	Exact match “Weston Solutions, Inc.(Weston) is a 100% employee-owned environmental and infrastructure services firm committed to safety and providing measurable client value.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
18	Partner Engineering & Science, INC	Exact match	Torrance, CA, United StatesHQ recorded Sep 19, 2026	1,001-5,000	1,358 contacts →
	Exact match “Partner Assessment Corp.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
19	Adec Innovations	Exact match	Irvine, CA, United StatesHQ recorded Sep 19, 2026	1,001-5,000	1,304 contacts →
	Exact match “ADEC Innovations seamlessly delivers fully integrated, cost-effective industry expertise, business process & data management, and software services.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
20	Knight Piesold	Exact match	Denver, CO, United StatesHQ recorded Sep 19, 2026	1,001-5,000	1,231 contacts →
	Exact match “Knight Piésold is an employee-owned, global consulting firm providing specialist services to the mining, power, water resources, and infrastructure industries.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
21	Verdantas	Exact match	Tampa, FL, United StatesHQ recorded Sep 19, 2026	1,001-5,000	1,139 contacts →
	Exact match “At Verdantas, we blend engineering and environmental science together with advanced technology and world-renowned labs to create solutions with the big picture in mind.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
22	Apex Companies	Exact match	Rockville, MD, United StatesHQ recorded Sep 19, 2026	1,001-5,000	1,137 contacts →
	Exact match “Who is Apex?” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
23	Haley & Aldrich	Exact match	Burlington, MA, United StatesHQ recorded Sep 19, 2026	501-1,000	1,124 contacts →
	Exact match “Haley & Aldrich is committed to solving our clients’ most meaningful challenges in the built and natural environments.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
24	Bge, INC	Exact match	Houston, TX, United StatesHQ recorded Sep 19, 2026	1,001-5,000	1,112 contacts →
	Exact match “Ranked No.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
25	Barr Engineering CO	Exact match	Minneapolis, MN, United StatesHQ recorded Sep 19, 2026	1,001-5,000	1,088 contacts →
	Exact match “Barr provides engineering and environmental consulting services to clients across the Midwest, throughout the Americas, and around the world.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase

RevenueBase SmartSearch

Describe a niche business in your own words. RevenueBase SmartSearch compares the meaning of your description with company business descriptions compiled in the RevenueBase company graph. Exact, Similar, Related and Broad control how closely companies must fit.

This list uses Exact for “environmental consulting companies”. Each Exact match badge shows membership in that saved search; it is not an individual similarity score or a service-quality rating. Recorded descriptions are shown where available.

Showing 25 of 6,096 environmental consulting companies based in the United States

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Environmental consulting companies based in the United States at a glance

As of Sep 19, 2026

47.0%Verified-email coverage

30.7Average contacts per company

1-10Median size (employees)

2.3%Largest-city concentration · Houston

Sep 19, 2026Page data refreshed

Companies by employee count

1-10

3,226

11-50

1,997

51-200

618

201-500

133

501-1,000

1,001-5,000

5,001-10,000

10001+

Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 6,096 companies.

How this list was built

The recorded descriptions help you assess these company matches. Check a company’s website for its current services and locations.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase SmartSearch, the natural-language company search available to every RevenueBase user.
What qualifies: Company records associated with the United States whose business descriptions match “environmental consulting companies” by meaning at the Exact setting. Descriptions are compiled in the RevenueBase company graph from public websites, profiles and company information where available; they are not guaranteed quotations from the company's website.
RevenueBase SmartSearch: Describe a niche company in your own words to find businesses by meaning. Exact, Similar, Related and Broad control the breadth of RevenueBase SmartSearch. This saved list uses Exact. Each row's Exact match badge shows inclusion in that search, not an individual score or a service-quality judgment.
Public preview: The public preview omits records without a verified work email. Where headquarters information is recorded, preview rows are also filtered to this page’s location. Dataset totals and geographic summaries describe the full matched records before these preview filters.
Match quality: RevenueBase's August 25, 2026 study assessed 4,198 description/company pairs across matching settings. The publisher reports 86% good or better at Exact. This evaluates the method across queries; it does not audit this individual list. Recorded company descriptions, where available, help you judge each match yourself. Read the full methodology: how the lists are built and what the study measures.
Ranking: Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification: Every displayed company carries at least one verified work email. RevenueBase tracks 88,013 professional contacts with verified work emails across the full matched dataset. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh: This page's figures were pulled from the company graph on September 19, 2026. Lists refresh periodically as the graph is re-checked.
Record context: Company records and descriptions can change. Check the company's website for its current services and locations.

Environmental consulting companies by metro

Frequently asked

What is RevenueBase SmartSearch?

RevenueBase SmartSearch finds niche companies by the meaning of their business descriptions in the RevenueBase company graph. Exact, Similar, Related and Broad control how closely companies must fit your description. This list uses Exact for “environmental consulting companies”; each Exact match badge shows search membership, not an individual similarity or quality score.

How many environmental consulting companies are there based in the United States?

RevenueBase identified 6,096 company matches for environmental consulting companies associated with the United States as of September 2026, using the meaning of business descriptions at Exact. This is the recorded matched set in the RevenueBase company graph.

What is the largest company on this list?

Tetra Tech tops the displayed preview by professional contacts tracked in RevenueBase. Recorded headquarters appear in the company rows.

Which city has the most environmental consulting companies?

Houston leads with 141 company records, followed by New York (95) and Seattle (66).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work limited free results with 500 credits to start. Upgrading provides access to the 88,013 professional contacts with verified work emails tracked across these 6,096 companies; direct dials are available where recorded.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 19, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase SmartSearch, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.