Company lists · Data refreshed September 2026

Top 25 Geological consulting services based in the United States

RevenueBase identified 3,437 geological consulting services headquartered in the United States as of September 2026 and tracks 74,420 professional contacts across them, including 34,626 with verified work emails. Houston is the largest hub.

This list covers geological consulting services headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 21, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, 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 HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 21, 2026 86% judged on-target in blind review
3,437Companies
74,420Contacts tracked
34,626Verified emails
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The 25 largest geological consulting services based in the United States

Ranked by team size
Top 25 of 3,437 geological consulting services based in the United States, ranked by team size, largest first. Data refreshed Sep 21, 2026. RevenueBase Smart Search rates how each company's information relates to geological consulting services: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Partial evidenceOlathe, KS, United StatesHQ checked Sep 21, 20265,001-10,0006,113 contacts →

Partial evidence

“Terracon is a 100 percent employee-owned consulting engineering firm providing quality services to clients.”

Source: RevenueBase Database · checked Sep 21, 2026
2Partial evidenceChantilly, VA, United StatesHQ checked Sep 21, 20261,001-5,0002,210 contacts →

Partial evidence

“ECS Group of Companies is a Chantilly, VA-based consulting engineering firm.”

Source: RevenueBase Database · checked Sep 21, 2026
3Indirect evidenceParsippany, NJ, United StatesHQ checked Sep 21, 20261,001-5,0002,177 contacts →

Indirect evidence

“Langan's client-focused, highly entrepreneurial culture cultivates an environment of opportunities in which career growth and teamwork flourish.”

Source: RevenueBase Database · checked Sep 21, 2026
4Indirect evidenceOrlando, FL, United StatesHQ checked Sep 21, 20261,001-5,0001,595 contacts →

Indirect evidence

“UES provides professional engineering, environmental, testing and inspection services to clients across the United States.”

Source: RevenueBase Database · checked Sep 21, 2026
5Indirect evidenceTorrance, CA, United StatesHQ checked Sep 21, 20261,001-5,0001,358 contacts →

Indirect evidence

“Partner Assessment Corp.”

Source: RevenueBase Database · checked Sep 21, 2026
6Partial evidenceDenver, CO, United StatesHQ checked Sep 21, 20261,001-5,0001,231 contacts →

Partial evidence

“Knight Piésold is an employee-owned, global consulting firm providing specialist services to the mining, power, water resources, and infrastructure industries.”

Source: RevenueBase Database · checked Sep 21, 2026
7Partial evidenceMinneapolis, MN, United StatesHQ checked Sep 21, 20261,001-5,0001,088 contacts →

Partial evidence

“Barr provides engineering and environmental consulting services to clients across the Midwest, throughout the Americas, and around the world.”

Source: RevenueBase Database · checked Sep 21, 2026
8Indirect evidenceNorwood, MA, United StatesHQ checked Sep 21, 2026501-1,000880 contacts →

Indirect evidence

“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…”

Source: RevenueBase Database · checked Sep 21, 2026
9Indirect evidenceGlen Allen, VA, United StatesHQ checked Sep 21, 2026501-1,000707 contacts →

Indirect evidence

“Schnabel is a trusted partner in building the foundation for project success.”

Source: RevenueBase Database · checked Sep 21, 2026
10Indirect evidenceMetairie, LA, United StatesHQ checked Sep 21, 2026501-1,000700 contacts →

Indirect evidence

“EDG Inc.”

Source: RevenueBase Database · checked Sep 21, 2026
11Indirect evidenceSan Antonio, TX, United StatesHQ checked Sep 21, 2026501-1,000582 contacts →

Indirect evidence

“Founded in 1968, Raba Kistner Inc.”

Source: RevenueBase Database · checked Sep 21, 2026
12Indirect evidenceHouston, TX, United StatesHQ checked Sep 21, 2026201-500521 contacts →

Indirect evidence

“SAExploration offers a full range of geophysical ground acquisition services from design, prospecting, drilling, recording and analysis of field quality, as well as mobilization…”

Source: RevenueBase Database · checked Sep 21, 2026
13Partial evidenceKennesaw, GA, United StatesHQ checked Sep 21, 2026501-1,000518 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 21, 2026
14Indirect evidenceRedmond, WA, United StatesHQ checked Sep 21, 2026201-500479 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 21, 2026
15Partial evidenceVentura, CA, United StatesHQ checked Sep 21, 2026501-1,000479 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 21, 2026
16Partial evidencePlymouth, MI, United StatesHQ checked Sep 21, 2026201-500459 contacts →

Partial evidence

“SME® is a professional consulting engineering firm in the geosciences, materials and the environment.”

Source: RevenueBase Database · checked Sep 21, 2026
17Indirect evidenceSan Diego, CA, United StatesHQ checked Sep 21, 2026501-1,000449 contacts →

Indirect evidence

“Ninyo & Moore was acquired by SOCOTEC US.”

Source: RevenueBase Database · checked Sep 21, 2026
18Indirect evidenceGreenwood Village, CO, United StatesHQ checked Sep 21, 20261,001-5,000449 contacts →

Indirect evidence

“Minova is an industry leader of ground support and geotechnical solutions for mining, tunnelling and surface ground engineering projects.”

Source: RevenueBase Database · checked Sep 21, 2026
19Indirect evidenceWall Township, NJ, United StatesHQ checked Sep 21, 2026201-500447 contacts →

Indirect evidence

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

Source: RevenueBase Database · checked Sep 21, 2026
20Indirect evidenceCherry Hill, NJ, United StatesHQ checked Sep 21, 2026501-1,000438 contacts →

Indirect evidence

“Founded in 1901, RVE has grown to be an industry leader with 500 team members in offices throughout New Jersey, Pennsylvania, Delaware, Maryland and North Carolina.”

Source: RevenueBase Database · checked Sep 21, 2026
21Partial evidenceLincolnshire, IL, United StatesHQ checked Sep 21, 2026201-500365 contacts →

Partial evidence

“Manhard Consulting has joined Atwell, a national consulting, engineering, and construction services firm with 2,100 technical professionals across the country.”

Source: RevenueBase Database · checked Sep 21, 2026
22Indirect evidenceParlin, NJ, United StatesHQ checked Sep 21, 2026201-500336 contacts →

Indirect evidence

“CME Associates, with eight (8) office locations throughout New Jersey, provides a complete range of Environmental, Geotechnical, Engineering, Surveying and Planning services.”

Source: RevenueBase Database · checked Sep 21, 2026
23Partial evidenceColumbus, OH, United StatesHQ checked Sep 21, 2026201-500314 contacts →

Partial evidence

“CTL Engineering is a full service consulting engineering, testing, inspection, and analytical services company.”

Source: RevenueBase Database · checked Sep 21, 2026
24Indirect evidenceRichmond, VA, United StatesHQ checked Sep 21, 2026201-500312 contacts →

Indirect evidence

“Established in 1881, Froehling & Robertson, Inc.”

Source: RevenueBase Database · checked Sep 21, 2026
25Indirect evidenceOrlando, FL, United StatesHQ checked Sep 21, 2026201-500311 contacts →

Indirect evidence

“Ardaman & Associates, Inc.”

Source: RevenueBase Database · checked Sep 21, 2026

Showing 25 of 3,437 geological consulting services based in the United States

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Geological consulting services based in the United States at a glance

As of Sep 21, 2026
46.5%Verified-email coverage
21.7Average contacts per company
11-50Median size (employees)
6.1%Largest-city concentration · Houston
Sep 21, 2026Page data refreshed

Companies by employee count

1-10
1,712
11-50
1,221
51-200
398
201-500
71
501-1,000
13
1,001-5,000
15
5,001-10,000
2
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 3,437 companies.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among geological consulting services, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source
The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies
Companies headquartered in the United States whose own description of what they do matches “geological consulting services”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search
RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names geological consulting services), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude
Companies whose own description does not clearly place them among geological consulting services, and records with no verified work email. Companies headquartered outside United States are excluded even when they keep an office there.
Match quality
In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
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 listed company carries at least one verified work email, 34,626 across the full list. 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 21, 2026. Lists refresh periodically as the graph is re-checked.
Corrections
Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names geological consulting services, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many geological consulting services are there based in the United States?

RevenueBase identified 3,437 geological consulting services headquartered in the United States as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

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

Which city has the most geological consulting services?

Houston leads with 208 headquartered companies, followed by Denver (55) and Dallas (37).

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 34,626 verified decision-maker contacts tracked across these 3,437 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 21, 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 Smart Search, 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.