Company lists · Data refreshed September 2026

Top 25 Ecological consulting firms based in the United States

Name: Ecological 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 1, 2026 4,819 companies tracked

RevenueBase identified 4,819 company matches for ecological consulting firms associated with the United States as of September 2026 and tracks 150,555 professional contacts across them, including 73,143 with verified work emails and 65,274 with mobile numbers. Houston is the largest hub.

This list covers company matches for ecological 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 1, 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 1, 2026 How this list was built

4,819Companies

150,555Contacts tracked

73,143Verified emails

65,274Mobile numbers

Explore this list → Free signup · no credit card · 500 free credits

The 25 largest ecological consulting firms based in the United States

Ranked by team size

Top 25 of 4,819 company matches for ecological consulting firms based in the United States, ordered by professional contacts tracked in RevenueBase, largest first. Recorded Sep 1, 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 1, 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 1, 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 1, 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 1, 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 1, 2026 · View company records in RevenueBase
6	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 1, 2026 · View company records in RevenueBase
7	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 1, 2026 · View company records in RevenueBase
8	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 1, 2026 · View company records in RevenueBase
9	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 1, 2026 · View company records in RevenueBase
10	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 1, 2026 · View company records in RevenueBase
11	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 1, 2026 · View company records in RevenueBase
12	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 1, 2026 · View company records in RevenueBase
13	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 1, 2026 · View company records in RevenueBase
14	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 1, 2026 · View company records in RevenueBase
15	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 1, 2026 · View company records in RevenueBase
16	Haley & Aldrich	Exact match	Burlington, MA, United States	501-1,000	1,128 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 1, 2026 · View company records in RevenueBase
17	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 1, 2026 · View company records in RevenueBase
18	Barr Engineering CO	Exact match	Washington, United States	1,001-5,000	1,098 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 1, 2026 · View company records in RevenueBase
19	Braun Intertec Corporation	Exact match	Amarillo, TX, United States	1,001-5,000	1,054 contacts →
	Exact match “At Braun Intertec, we work at the intersection of the natural and built environments, combining science, technology, and engineering.” Recorded in the RevenueBase company graph · Sep 1, 2026 · View company records in RevenueBase
20	Trinity Consultants	Exact match	Dallas, TX, United States	1,001-5,000	949 contacts →
	Exact match “Trinity Consultants is a global team of experts helping organizations solve complex challenges in environmental compliance, ecological protection, infrastructure performance, and…” Recorded in the RevenueBase company graph · Sep 1, 2026 · View company records in RevenueBase
21	Alliance Technical Group	Exact match	Pittsburgh, PA, United States	1,001-5,000	946 contacts →
	Exact match “Alliance is a new kind of environmental services company-powered by innovation, focused on service, and committed to client success.” Recorded in the RevenueBase company graph · Sep 1, 2026 · View company records in RevenueBase
22	Parametrix	Exact match	Berkeley, CA, United States	501-1,000	875 contacts →
	Exact match “At Parametrix, we help our clients imagine what's possible.” Recorded in the RevenueBase company graph · Sep 1, 2026 · View company records in RevenueBase
23	GZA Geoenvironmental, INC	Exact match	Boston, MA, United States	501-1,000	872 contacts →
	Exact match “Founded in 1964 as a soils and foundations specialty consultant, GZA GeoEnvironmental, Inc.(GZA) has grown into a full-service company providing its clients with highly…” Recorded in the RevenueBase company graph · Sep 1, 2026 · View company records in RevenueBase
24	ATC Group Services LLC	Exact match	Sharonville, OH, United States	1,001-5,000	868 contacts →
	Exact match “ATC Group Services LLC is now Atlas.” Recorded in the RevenueBase company graph · Sep 1, 2026 · View company records in RevenueBase
25	ENVU	Exact match	Cary, NC, United States	1,001-5,000	822 contacts →
	Exact match “At Envu, we partner with our customers to design world-class, forward-thinking innovations that protect and enhance the health of environments around the world.” Recorded in the RevenueBase company graph · Sep 1, 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 “ecological 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 4,819 ecological consulting firms based in the United States

See the full list, filter by size, metro and specialty, and access 73,143 tracked professional contacts with verified work emails. Direct dials are available where recorded.

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Ecological consulting firms based in the United States at a glance

As of Sep 1, 2026

48.6%Verified-email coverage

43.4%Mobile-number coverage

31.2Average contacts per company

1-10Median size (employees)

1.6%Largest-city concentration · Houston

Sep 1, 2026Page data refreshed

Companies by employee count

1-10

2,796

11-50

1,471

51-200

372

201-500

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 “ecological 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 73,143 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 1, 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.

Ecological 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 “ecological consulting firms”; each Exact match badge shows search membership, not an individual similarity or quality score.

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

RevenueBase identified 4,819 company matches for ecological 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 ecological consulting firms?

Houston leads with 77 company records, followed by New York (70) and Portland (64).

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 73,143 professional contacts with verified work emails tracked across these 4,819 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 1, 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.