Company lists · Data refreshed September 2026

Top 25 Compliance and environmental consulting firms based in the United States

Name: Compliance and environmental consulting firms based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 27, 2026 7,098 companies tracked

RevenueBase identified 7,098 company matches for compliance and environmental consulting firms associated with the United States as of September 2026 and tracks 176,270 professional contacts across them, including 79,543 with verified work emails. Houston is the largest hub.

This list covers company matches for compliance and environmental consulting firms 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 27, 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 27, 2026 How this list was built

7,098Companies

176,270Contacts tracked

79,543Verified emails

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The 25 largest compliance and environmental consulting firms based in the United States

Ranked by team size

Top 25 of 7,098 company matches for compliance and environmental consulting firms based in the United States, ordered by professional contacts tracked in RevenueBase, largest first. Recorded Sep 27, 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 27, 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 27, 2026 · View company records in RevenueBase
2	Terracon	Exact match	Olathe, KS, United StatesHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
3	APTIM	Exact match	Baton Rouge, LA, United StatesHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
4	Brown And Caldwell	Exact match	Walnut Creek, CA, United StatesHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
5	Geosyntec Consultants	Exact match	Boca Raton, FL, United StatesHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
6	Providence	Exact match	Baton Rouge, LA, United StatesHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
7	ECS Group Of Companies	Exact match	Chantilly, VA, United StatesHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
8	Langan Engineering & Environmental Services	Exact match	Parsippany, NJ, United StatesHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
9	Civil & Environmental Consultants, INC	Exact match	Moon Township, PA, United StatesHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
10	Hazen And Sawyer	Exact match	New York, NY, United StatesHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
11	IMEG	Exact match	Rock Island, IL, United StatesHQ recorded Sep 27, 2026	1,001-5,000	1,985 contacts →
	Exact match “Leaders in Engineering and Innovation.” Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
12	Swca Environmental Consultants	Exact match	Phoenix, AZ, United StatesHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
13	GEI Consultants, INC	Exact match	Woburn, MA, United StatesHQ recorded Sep 27, 2026	1,001-5,000	1,604 contacts →
	Exact match Recorded description not available. Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
14	UES	Exact match	Orlando, FL, United StatesHQ recorded Sep 27, 2026	1,001-5,000	1,595 contacts →
	Exact match “UES provides professional engineering, environmental, testing and inspection services to clients across the United States.” Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
15	Exponent	Exact match	Menlo Park, CA, United StatesHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
16	Montrose Environmental Group	Exact match	Little Rock, AR, United StatesHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
17	Weston Solutions, INC	Exact match	West Chester, PA, United StatesHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
18	Partner Engineering & Science, INC	Exact match	Torrance, CA, United StatesHQ recorded Sep 27, 2026	1,001-5,000	1,358 contacts →
	Exact match “Partner Assessment Corp.” Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
19	Sphera	Exact match	Chicago, IL, United StatesHQ recorded Sep 27, 2026	1,001-5,000	1,349 contacts →
	Exact match “Sphera creates a safer, more sustainable and productive world.” Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
20	Adec Innovations	Exact match	Irvine, CA, United StatesHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
21	Knight Piesold	Exact match	Denver, CO, United StatesHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
22	Verdantas	Exact match	Tampa, FL, United StatesHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
23	Apex Companies	Exact match	Rockville, MD, United StatesHQ recorded Sep 27, 2026	1,001-5,000	1,137 contacts →
	Exact match “Who is Apex?” Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
24	Barr Engineering CO	Exact match	Minneapolis, MN, United StatesHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
25	Triumvirate Environmental	Exact match	Somerville, MA, United StatesHQ recorded Sep 27, 2026	1,001-5,000	1,068 contacts →
	Exact match “Triumvirate Environmental provides sustainable environmental solutions to leading companies in the Life Sciences, Healthcare, Education, and Advanced Manufacturing markets.” Recorded in the RevenueBase company graph · Sep 27, 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 “compliance and environmental consulting firms”. 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 7,098 compliance and environmental consulting firms based in the United States

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Compliance and environmental consulting firms based in the United States at a glance

As of Sep 27, 2026

45.1%Verified-email coverage

24.8Average contacts per company

1-10Median size (employees)

2.6%Largest-city concentration · Houston

Sep 27, 2026Page data refreshed

Companies by employee count

1-10

4,084

11-50

2,174

51-200

611

201-500

125

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 7,098 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 “compliance and environmental consulting firms” 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 79,543 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 27, 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.

Compliance and environmental consulting firms 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 “compliance and environmental consulting firms”; each Exact match badge shows search membership, not an individual similarity or quality score.

How many compliance and environmental consulting firms are there based in the United States?

RevenueBase identified 7,098 company matches for compliance and environmental consulting firms 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 compliance and environmental consulting firms?

Houston leads with 188 company records, followed by New York (178) and Denver (84).

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 79,543 professional contacts with verified work emails tracked across these 7,098 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 27, 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.