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Company lists · Data verified August 2026

Top 25 Environmental consulting firms based in the United States

Compiled by the RevenueBase Data Team Verified Aug 28, 2026 7,084 companies tracked

There are 7,084 environmental consulting firms headquartered in the United States (RevenueBase, August 2026). RevenueBase 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 environmental consulting firms headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Data current as of August 28, 2026.

7,084Companies
226,716Contacts tracked
105,429Verified emails
98,188Mobile numbers
Unlock all 7,084 companies Free account · no credit card · 2 minutes

The 25 largest environmental consulting firms based in the United States

Ranked by team size
Top 25 of 7,084 environmental consulting firms based in the United States, ranked by team size, largest first. Data verified Aug 28, 2026. Click a count to unlock that company's people.
#CompanyHQEmployeesContactsVerified emails
1TerraconTustin, CA5,001-10,0006,0243,163
2GolderHouston, TX5,001-10,0003,1831,044
3APTIMWichita, KS1,001-5,0002,6441,098
4Brown And CaldwellWalnut Creek, CA1,001-5,0002,4551
5Geosyntec ConsultantsBoca Raton, FL1,001-5,0002,3921,594
6ECS Group Of CompaniesFredericksburg, VA1,001-5,0002,2011,061
7Civil & Environmental Consultants, INCMartinsburg, WV1,001-5,0002,152945
8Langan Engineering & Environmental ServicesEl Segundo, CA1,001-5,0002,1361,662
9RicardoCalifornia, MD1,001-5,0002,111955
10Hazen And SawyerRaleigh, NC1,001-5,0002,1051,457
11LJASarasota, FL1,001-5,0002,0731,578
12IMEGRock Island, IL1,001-5,0001,954255
13Carollo EngineersOklahoma City, OK1,001-5,0001,7091,142
14Swca Environmental ConsultantsPhoenix, AZ1,001-5,0001,6181,159
15GEI Consultants, INCWoburn, MA1,001-5,0001,5771,237
16UESHouston, TX1,001-5,0001,571879
17Montrose Environmental GroupLittle Rock, AR1,001-5,0001,516846
18ATLASDenver, CO1,001-5,0001,5151,073
19Weston Solutions, INCWest Chester, PA1,001-5,0001,450671
20Partner Engineering & Science, INCPasadena, CA1,001-5,0001,348984
21SCS EngineersLong Beach, CA1,001-5,0001,191675
22RimkusOmaha, NE1,001-5,0001,170719
23Apex CompaniesRockville, MD1,001-5,0001,146591
24Bge, INCVero Beach, FL1,001-5,0001,129682
25VerdantasToledo, OH1,001-5,0001,127795

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 Aug 28, 2026
1-10Median size (employees)
HoustonLargest hub · 133 HQs
98,188Contacts with mobile numbers
0Emails re-verified in last 30 days

Companies by employee count

1-10
3,795
11-50
2,274
51-200
706
201-500
156
501-1,000
54
1,001-5,000
58
5,001-10,000
9

Environmental consulting firms by metro

MetroCompanies
Environmental consulting firms in Houston133
Environmental consulting firms in New York117
Environmental consulting firms in Seattle80
Environmental consulting firms in Washington76
Environmental consulting firms in Portland70
Environmental consulting firms in Denver66
Environmental consulting firms in Los Angeles63

How this list was built

Source
The RevenueBase company graph: 21.3 million companies and 398.9 million professional contacts resolved from primary sources.
Inclusion
Companies whose own business descriptions match “environmental consulting firms”, with match quality audited by blind human judging, and headquartered in the United States.
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
Contact records re-verify on a rolling cadence; 0 contacts on this list were re-verified in the last 30 days.
Refresh
Lists are refreshed periodically as the underlying company graph is re-verified. Last verified Aug 28, 2026.

Frequently asked

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

There are 7,084 environmental consulting firms headquartered in the United States as of August 2026 (RevenueBase).

What is the largest company on this list?

Terracon, headquartered in Tustin, tops this list with the largest team on record.

Which city has the most environmental consulting firms?

Houston leads with 133 headquartered companies, 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 the top results, verified emails and direct dials included. Upgrading unlocks all 105,429 verified decision-maker contacts tracked across these 7,084 companies.

How current is this list?

The list is refreshed periodically as the underlying company graph is re-verified. It was last verified on August 28, 2026.

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Related lists

Browse: Companies home · All United States lists · All Environmental consulting firms lists · New lists

About this data

RevenueBase is a B2B contact data platform. Its company graph covers 21.3 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, the same data that powers RevenueBase's B2B data products and the free research portal.

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