Company lists · Data refreshed September 2026

Top 25 Environmental impact assessment firms based in the United States

RevenueBase identified 2,374 company matches for environmental impact assessment firms associated with the United States as of September 2026 and tracks 62,486 professional contacts across them, including 32,547 with verified work emails. Houston is the largest hub.

This list covers company matches for environmental impact assessment 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 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
2,374Companies
62,486Contacts tracked
32,547Verified emails
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The 25 largest environmental impact assessment firms based in the United States

Ranked by team size
Top 25 of 2,374 company matches for environmental impact assessment firms 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.
#CompanyRevenueBase SmartSearchHeadquartersEmployeesContacts
1Exact matchBoca Raton, FL, United StatesHQ recorded Sep 19, 20261,001-5,0002,393 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
2Exact matchBaton Rouge, LA, United StatesHQ recorded Sep 19, 2026n/a2,232 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
3Exact matchParsippany, NJ, United StatesHQ recorded Sep 19, 20261,001-5,0002,177 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
4Exact matchMoon Township, PA, United StatesHQ recorded Sep 19, 20261,001-5,0002,145 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
5Exact matchPhoenix, AZ, United StatesHQ recorded Sep 19, 20261,001-5,0001,629 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
6Exact matchLittle Rock, AR, United StatesHQ recorded Sep 19, 20261,001-5,0001,529 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
7Exact matchWest Chester, PA, United StatesHQ recorded Sep 19, 20261,001-5,0001,441 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
8Exact matchRockville, MD, United StatesHQ recorded Sep 19, 20261,001-5,0001,137 contacts →

Exact match

“Who is Apex?”

Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
9Exact matchMinneapolis, MN, United StatesHQ recorded Sep 19, 20261,001-5,0001,088 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
10Exact matchDallas, TX, United StatesHQ recorded Sep 19, 20261,001-5,000961 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 19, 2026 · View company records in RevenueBase
11Exact matchDecatur, AL, United StatesHQ recorded Sep 19, 20261,001-5,000956 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 19, 2026 · View company records in RevenueBase
12Exact matchSeattle, WA, United StatesHQ recorded Sep 19, 2026501-1,000880 contacts →

Exact match

“At Parametrix, we help our clients imagine what's possible.”

Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
13Exact matchLafayette, LA, United StatesHQ recorded Sep 19, 20261,001-5,000865 contacts →

Exact match

“ATC Group Services LLC is now Atlas.”

Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
14Exact matchEncinitas, CA, United StatesHQ recorded Sep 19, 2026501-1,000795 contacts →

Exact match

“Dudek is an environmental, planning, and engineering consulting firm.”

Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
15Exact matchSan Francisco, CA, United StatesHQ recorded Sep 19, 2026501-1,000732 contacts →

Exact match

“ESA is a 100% employee-owned environmental consulting firm.”

Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
16Exact matchSt. Paul, MN, United StatesHQ recorded Sep 19, 20261,001-5,000658 contacts →

Exact match

“Antea Group is an international engineering and environmental consulting firm specializing in full-service solutions in the fields of environment, health and safety, and…”

Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
17Exact matchBurlington, MA, United StatesHQ recorded Sep 19, 2026501-1,000535 contacts →

Exact match

“For 35 years we have been helping investors, lenders, owners, developers, contractors, and property managers reduce risk and optimize their built facilities, infrastructure and…”

Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
18Exact matchKennesaw, GA, United StatesHQ recorded Sep 19, 2026501-1,000518 contacts →

Exact match

“Established in 1996, NOVA was originally founded to provide Environmental Consulting, Geotechnical Engineering, and Construction Materials Testing and Inspection services to the…”

Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
19Exact matchBoston, MA, United StatesHQ recorded Sep 19, 202651-200504 contacts →

Exact match

“BSC Group, Inc.(BSC) is a multidisciplinary consulting firm with a staff of more than 200 professionals and offices in Boston, Worcester, Andover, and West Yarmouth, MA, as well…”

Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
20Exact matchSeattle, WA, United StatesHQ recorded Sep 19, 2026501-1,000479 contacts →

Exact match

“Headquartered in Seattle, Washington, Anchor QEA is a nationally recognized environmental science and engineering consulting firm specializing in aquatic, shoreline, and water…”

Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
21Exact matchVentura, CA, United StatesHQ recorded Sep 19, 2026501-1,000479 contacts →

Exact match

“Rincon Consultants is a multi-disciplinary environmental sciences, planning, and engineering consulting firm that provides quality professional services to government and industry.”

Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
22Exact matchWall Township, NJ, United StatesHQ recorded Sep 19, 2026201-500447 contacts →

Exact match

“We are Groundwater & Environmental Services, Inc, better known as GES.”

Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
23Exact matchIslandia, NY, United StatesHQ recorded Sep 19, 2026201-500433 contacts →

Exact match

“Founded 40 years ago, Roux is recognized for being a highly effective, client-focused environmental consulting and management firm.”

Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
24Exact matchWalnut Creek, CA, United StatesHQ recorded Sep 19, 2026201-500433 contacts →

Exact match

“AEI Consultants provides building, environmental, land and sustainability assessment and consulting services throughout North America.”

Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
25Exact matchReston, VA, United StatesHQ recorded Sep 19, 2026501-1,000430 contacts →

Exact match

“HydroGeoLogic, Inc.(HGL) is an employee-owned company with over 36 years of experience developing innovative, effective, and sustainable engineering and remediation solutions to…”

Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase

Showing 25 of 2,374 environmental impact assessment firms based in the United States

See the full list, filter by size, metro and specialty, and access 32,547 tracked professional contacts with verified work emails. Direct dials are available where recorded.

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Environmental impact assessment firms based in the United States at a glance

As of Sep 19, 2026
52.1%Verified-email coverage
26.3Average contacts per company
1-10Median size (employees)
2.2%Largest-city concentration · Houston
Sep 19, 2026Page data refreshed

Companies by employee count

1-10
1,253
11-50
839
51-200
206
201-500
37
501-1,000
14
1,001-5,000
20
5,001-10,000
1
10001+
1

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 2,374 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 impact assessment 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 32,547 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.

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 impact assessment firms”; each Exact match badge shows search membership, not an individual similarity or quality score.

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

RevenueBase identified 2,374 company matches for environmental impact assessment 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?

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

Which city has the most environmental impact assessment firms?

Houston leads with 53 company records, followed by New York (33) and Seattle (29).

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 32,547 professional contacts with verified work emails tracked across these 2,374 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.