Company lists · Data refreshed September 2026

Top 25 Environmental consulting firms based in the United States

Name: 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 2, 2026 7,084 companies tracked

RevenueBase identified 7,084 company matches for environmental consulting firms associated with the United States as of September 2026 and tracks 226,716 professional contacts across them, including 105,429 with verified work emails and 98,188 with mobile numbers. Houston is the largest hub.

This list covers company matches for 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 2, 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 2, 2026 How this list was built

7,084Companies

226,716Contacts tracked

105,429Verified emails

98,188Mobile numbers

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The 25 largest environmental consulting firms based in the United States

Ranked by team size

Top 25 of 7,084 company matches for environmental consulting firms based in the United States, ordered by professional contacts tracked in RevenueBase, largest first. Recorded Sep 2, 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	Terracon	Exact match	Tustin, CA, United States	5,001-10,000	6,024 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 2, 2026 · View company records in RevenueBase
2	Golder	Exact match	Houston, TX, United States	5,001-10,000	3,183 contacts →
	Exact match “Golder was acquired by WSP.” Recorded in the RevenueBase company graph · Sep 2, 2026 · View company records in RevenueBase
3	APTIM	Exact match	Wichita, KS, United States	1,001-5,000	2,644 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 2, 2026 · View company records in RevenueBase
4	Brown And Caldwell	Exact match	Walnut Creek, CA, United States	1,001-5,000	2,455 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 2, 2026 · View company records in RevenueBase
5	Geosyntec Consultants	Exact match	Boca Raton, FL, United States	1,001-5,000	2,392 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 2, 2026 · View company records in RevenueBase
6	ECS Group Of Companies	Exact match	Fredericksburg, VA, United States	1,001-5,000	2,201 contacts →
	Exact match “ECS Group of Companies is a Chantilly, VA-based consulting engineering firm.” Recorded in the RevenueBase company graph · Sep 2, 2026 · View company records in RevenueBase
7	Civil & Environmental Consultants, INC	Exact match	Martinsburg, WV, United States	1,001-5,000	2,152 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 2, 2026 · View company records in RevenueBase
8	Langan Engineering & Environmental Services	Exact match	El Segundo, CA, United States	1,001-5,000	2,136 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 2, 2026 · View company records in RevenueBase
9	Ricardo	Exact match	California, MD, United States	1,001-5,000	2,111 contacts →
	Exact match “Ricardo, a member of @WSP, is a global strategic, environmental, and engineering consulting company.” Recorded in the RevenueBase company graph · Sep 2, 2026 · View company records in RevenueBase
10	Hazen And Sawyer	Exact match	Raleigh, NC, United States	1,001-5,000	2,105 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 2, 2026 · View company records in RevenueBase
11	LJA	Exact match	Sarasota, FL, United States	1,001-5,000	2,073 contacts →
	Exact match “Employee-Owned.” Recorded in the RevenueBase company graph · Sep 2, 2026 · View company records in RevenueBase
12	IMEG	Exact match	Rock Island, IL, United States	1,001-5,000	1,954 contacts →
	Exact match “Leaders in Engineering and Innovation.” Recorded in the RevenueBase company graph · Sep 2, 2026 · View company records in RevenueBase
13	Carollo Engineers	Exact match	Oklahoma City, OK, United States	1,001-5,000	1,709 contacts →
	Exact match “For more than 90 years, Carollo Engineers has been dedicated exclusively to water and wastewater solutions.” Recorded in the RevenueBase company graph · Sep 2, 2026 · View company records in RevenueBase
14	Swca Environmental Consultants	Exact match	Phoenix, AZ, United States	1,001-5,000	1,618 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 2, 2026 · View company records in RevenueBase
15	GEI Consultants, INC	Exact match	Woburn, MA, United States	1,001-5,000	1,577 contacts →
	Exact match Recorded description not available. Recorded in the RevenueBase company graph · Sep 2, 2026 · View company records in RevenueBase
16	UES	Exact match	Houston, TX, United States	1,001-5,000	1,571 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 2, 2026 · View company records in RevenueBase
17	Montrose Environmental Group	Exact match	Little Rock, AR, United States	1,001-5,000	1,516 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 2, 2026 · View company records in RevenueBase
18	ATLAS	Exact match	Denver, CO, United States	1,001-5,000	1,515 contacts →
	Exact match “Atlas Technical Consultants (Atlas) provides professional testing, inspection, engineering, environmental and consulting services nationwide.” Recorded in the RevenueBase company graph · Sep 2, 2026 · View company records in RevenueBase
19	Weston Solutions, INC	Exact match	West Chester, PA, United States	1,001-5,000	1,450 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 2, 2026 · View company records in RevenueBase
20	Partner Engineering & Science, INC	Exact match	Pasadena, CA, United States	1,001-5,000	1,348 contacts →
	Exact match “Partner Assessment Corp.” Recorded in the RevenueBase company graph · Sep 2, 2026 · View company records in RevenueBase
21	SCS Engineers	Exact match	Long Beach, CA, United States	1,001-5,000	1,191 contacts →
	Exact match “SCS Engineers delivers environmental solutions by combining long-term experience with compliance and technological expertise.” Recorded in the RevenueBase company graph · Sep 2, 2026 · View company records in RevenueBase
22	Rimkus	Exact match	Omaha, NE, United States	1,001-5,000	1,170 contacts →
	Exact match “Consultants.” Recorded in the RevenueBase company graph · Sep 2, 2026 · View company records in RevenueBase
23	Apex Companies	Exact match	Rockville, MD, United States	1,001-5,000	1,146 contacts →
	Exact match “Who is Apex?” Recorded in the RevenueBase company graph · Sep 2, 2026 · View company records in RevenueBase
24	Bge, INC	Exact match	Vero Beach, FL, United States	1,001-5,000	1,129 contacts →
	Exact match “Ranked No.” Recorded in the RevenueBase company graph · Sep 2, 2026 · View company records in RevenueBase
25	Verdantas	Exact match	Toledo, OH, United States	1,001-5,000	1,127 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 2, 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 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 7,084 environmental consulting firms based in the United States

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Environmental consulting firms based in the United States at a glance

As of Sep 2, 2026

46.5%Verified-email coverage

43.3%Mobile-number coverage

32.0Average contacts per company

1-10Median size (employees)

1.9%Largest-city concentration · Houston

Sep 2, 2026Page data refreshed

Companies by employee count

1-10

3,795

11-50

2,274

51-200

706

201-500

156

501-1,000

1,001-5,000

5,001-10,000

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 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 105,429 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 2, 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 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 “environmental consulting firms”; each Exact match badge shows search membership, not an individual similarity or quality score.

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

RevenueBase identified 7,084 company matches for 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?

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

Which city has the most environmental consulting firms?

Houston leads with 133 company records, followed by New York (117) and Seattle (80).

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 105,429 professional contacts with verified work emails tracked across these 7,084 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 2, 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.