Company lists · Data refreshed November 2026

Top 25 Ecological engineering firms based in the United States

Name: Ecological engineering firms based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Nov 6, 2026 5,202 companies tracked

RevenueBase identified 5,202 company matches for ecological engineering firms associated with the United States as of November 2026 and tracks 237,596 professional contacts across them, including 119,396 with verified work emails. Houston is the largest hub.

This list covers company matches for ecological engineering 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 November 6, 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 Nov 6, 2026 How this list was built

5,202Companies

237,596Contacts tracked

119,396Verified emails

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The 25 largest ecological engineering firms based in the United States

Ranked by team size

Top 25 of 5,202 company matches for ecological engineering firms based in the United States, ordered by professional contacts tracked in RevenueBase, largest first. Recorded Nov 6, 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	Tetra Tech	Exact match	Pasadena, CA, United StatesHQ recorded Nov 6, 2026	10001+	14,232 contacts →
	Exact match “Tetra Tech is the leader in water, environment and sustainable infrastructure, providing high-end technical and engineering services for projects worldwide.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
2	WSP In The U.S	Exact match	New York, NY, United StatesHQ recorded Nov 6, 2026	10001+	10,188 contacts →
	Exact match “What if you could shape built and natural environments – and the future of those that use them?” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
3	CDM Smith	Exact match	Boston, MA, United StatesHQ recorded Nov 6, 2026	5,001-10,000	8,143 contacts →
	Exact match “CDM Smith is shaping what’s next, now, with world class solutions in water, environment, transportation and energy to public and private clients worldwide.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
4	Terracon	Exact match	Olathe, NE, United StatesHQ recorded Nov 6, 2026	5,001-10,000	6,576 contacts →
	Exact match “Terracon is a 100 percent employee-owned consulting engineering firm providing quality services to clients.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
5	APTIM	Exact match	Baton Rouge, OH, United StatesHQ recorded Nov 6, 2026	1,001-5,000	2,751 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 · Nov 6, 2026 · View company records in RevenueBase
6	Geosyntec Consultants	Exact match	Boca Raton, FL, United StatesHQ recorded Nov 6, 2026	1,001-5,000	2,553 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 · Nov 6, 2026 · View company records in RevenueBase
7	Brown And Caldwell	Exact match	Walnut Creek, CA, United StatesHQ recorded Nov 6, 2026	1,001-5,000	2,553 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 · Nov 6, 2026 · View company records in RevenueBase
8	Langan Engineering & Environmental Services	Exact match	Parsippany, TN, United StatesHQ recorded Nov 6, 2026	1,001-5,000	2,492 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 · Nov 6, 2026 · View company records in RevenueBase
9	ECS Group Of Companies	Exact match	Chantilly, VA, United StatesHQ recorded Nov 6, 2026	1,001-5,000	2,363 contacts →
	Exact match “ECS Group of Companies is a Chantilly, VA-based consulting engineering firm.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
10	Hazen And Sawyer	Exact match	New York, CO, United StatesHQ recorded Nov 6, 2026	1,001-5,000	2,306 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 · Nov 6, 2026 · View company records in RevenueBase
11	Olsson	Exact match	Lincoln, AR, United StatesHQ recorded Nov 6, 2026	1,001-5,000	2,289 contacts →
	Exact match “Olsson is an engineering firm made up of people who craft expert solutions and designs that improve communities.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
12	Civil & Environmental Consultants, INC	Exact match	Moon Township, MO, United StatesHQ recorded Nov 6, 2026	1,001-5,000	2,276 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 · Nov 6, 2026 · View company records in RevenueBase
13	Providence	Exact match	Baton Rouge, LA, United StatesHQ recorded Nov 6, 2026	n/a	2,268 contacts →
	Exact match “Providence is an employee-owned engineering and environmental consulting firm.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
14	IMEG	Exact match	Rock Island, IL, United StatesHQ recorded Nov 6, 2026	1,001-5,000	2,116 contacts →
	Exact match “Leaders in Engineering and Innovation.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
15	Carollo Engineers	Exact match	Walnut Creek, NV, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,837 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 · Nov 6, 2026 · View company records in RevenueBase
16	Bowman Consulting	Exact match	Reston, VA, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,827 contacts →
	Exact match “Headquartered in Reston, Virginia, Bowman is a national engineering services firm delivering infrastructure solutions to customers who own, develop and maintain the built…” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
17	Swca Environmental Consultants	Exact match	Phoenix, MA, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,695 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 · Nov 6, 2026 · View company records in RevenueBase
18	GEI Consultants, INC	Exact match	Woburn, MA, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,675 contacts →
	Exact match Recorded description not available. Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
19	Freese And Nichols	Exact match	Fort Worth, TX, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,588 contacts →
	Exact match “Freese and Nichols is a professional planning, consulting and engineering firm serving clients across the United States.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
20	Weston Solutions, INC	Exact match	West Chester, PA, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,559 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 · Nov 6, 2026 · View company records in RevenueBase
21	Ulteig	Exact match	Fargo, IA, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,491 contacts →
	Exact match “Ulteig delivers comprehensive design engineering, program management and technical and field services that strengthen infrastructure vital to everyday life.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
22	Partner Engineering & Science, INC	Exact match	Torrance, WA, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,481 contacts →
	Exact match “Partner Assessment Corp.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
23	Pennoni	Exact match	Philadelphia, DE, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,322 contacts →
	Exact match “Since our founding more than five decades ago, our clients trust Pennoni’s commitment to elevating the impact of projects on our communities.” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
24	Apex Companies	Exact match	Rockville, MD, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,321 contacts →
	Exact match “Who is Apex?” Recorded in the RevenueBase company graph · Nov 6, 2026 · View company records in RevenueBase
25	Verdantas	Exact match	Tampa, FL, United StatesHQ recorded Nov 6, 2026	1,001-5,000	1,275 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 · Nov 6, 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 engineering 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 5,202 ecological engineering firms based in the United States

See the full list, filter by size, metro and specialty, and access 119,396 tracked professional contacts with verified work emails. Direct dials are available where recorded.

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Ecological engineering firms based in the United States at a glance

As of Nov 6, 2026

50.3%Verified-email coverage

45.7Average contacts per company

11-50Median size (employees)

1.6%Largest-city concentration · Houston

Nov 6, 2026Page data refreshed

Companies by employee count

1-10

2,456

11-50

1,852

51-200

617

201-500

144

501-1,000

1,001-5,000

5,001-10,000

10001+

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 5,202 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 “ecological engineering 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 119,396 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 November 6, 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 engineering 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 engineering firms”; each Exact match badge shows search membership, not an individual similarity or quality score.

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

RevenueBase identified 5,202 company matches for ecological engineering firms associated with the United States as of November 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?

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

Which city has the most ecological engineering firms?

Houston leads with 81 company records, followed by New York (73) and Austin (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 119,396 professional contacts with verified work emails tracked across these 5,202 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 November 6, 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.