Company lists · Data refreshed September 2026

Top 25 Sustainable development firms based in the United States

RevenueBase identified 1,649 sustainable development firms headquartered in the United States as of September 2026 and tracks 22,467 professional contacts across them, including 8,746 with verified work emails. New York is the largest hub.

This list covers sustainable development 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. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 22, 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 22, 2026 86% judged on-target in blind review
1,649Companies
22,467Contacts tracked
8,746Verified emails
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The 25 largest sustainable development firms based in the United States

Ranked by team size
Top 25 of 1,649 sustainable development firms based in the United States, ranked by team size, largest first. Data refreshed Sep 22, 2026. RevenueBase Smart Search rates how each company's information relates to sustainable development firms: 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
1Indirect evidenceWashington, DC, United StatesHQ checked Sep 22, 20261,001-5,0004,410 contacts →

Indirect evidence

“In a world where conditions are changing faster, resources are tighter, and the path to results is increasingly complex, delivery matters more than ever.”

Source: RevenueBase Database · checked Sep 22, 2026
2Indirect evidencePhoenix, AZ, United StatesHQ checked Sep 22, 20261,001-5,0001,629 contacts →

Indirect evidence

“Founded on a commitment to sound science and creative solutions, SWCA is a leader in environmental and management consulting services.”

Source: RevenueBase Database · checked Sep 22, 2026
3Partial evidenceAustin, TX, United StatesHQ checked Sep 22, 2026n/a1,145 contacts →

Partial evidence

“OLA Sustainability, LLC OLA Sustainability is a consulting firm that focuses on integrating sustainable practices into commercial and multifamily design projects.”

Source: RevenueBase Database · checked Sep 22, 2026
4Indirect evidenceBurlington, MA, United StatesHQ checked Sep 22, 2026501-1,000535 contacts →

Indirect evidence

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

Source: RevenueBase Database · checked Sep 22, 2026
5Indirect evidenceIrvine, CA, United StatesHQ checked Sep 22, 2026201-500383 contacts →

Indirect evidence

“We are Trio – built from Edison Energy, Alfa Energy, and Altenex Energy.”

Source: RevenueBase Database · checked Sep 22, 2026
6Partial evidenceLong Beach, CA, United StatesHQ checked Sep 22, 2026201-500375 contacts →

Partial evidence

“P2S has brought forward-thinking, sustainable engineering solutions to California, the Pacific Northwest, and beyond, for over 30 years.”

Source: RevenueBase Database · checked Sep 22, 2026
7Indirect evidenceEvansville, WY, United StatesHQ checked Sep 22, 20261,001-5,000358 contacts →

Indirect evidence

“TAKKION is Moving Energy Forward.”

Source: RevenueBase Database · checked Sep 22, 2026
8Indirect evidencePark Ridge, NJ, United StatesHQ checked Sep 22, 2026201-500336 contacts →

Indirect evidence

“National Utility Service, Inc.”

Source: RevenueBase Database · checked Sep 22, 2026
9Partial evidenceGainesville, FL, United StatesHQ checked Sep 22, 2026201-500305 contacts →

Partial evidence

“Environmental Consulting & Technology, Inc.(ECT) is a multi-disciplinary environmental and sustainability consulting firm delivering strategy, permitting, design, and management…”

Source: RevenueBase Database · checked Sep 22, 2026
10Indirect evidenceBaton Rouge, LA, United StatesHQ checked Sep 22, 202651-200305 contacts →

Indirect evidence

“CSRS was acquired by Westwood Professional Services on June 30, 2025.”

Source: RevenueBase Database · checked Sep 22, 2026
11Indirect evidenceLancaster, NY, United StatesHQ checked Sep 22, 20265,001-10,000278 contacts →

Indirect evidence

“E&E is now WSP USA.”

Source: RevenueBase Database · checked Sep 22, 2026
12Indirect evidenceAustin, CA, United StatesHQ checked Sep 22, 2026201-500275 contacts →

Indirect evidence

“The world runs on power.”

Source: RevenueBase Database · checked Sep 22, 2026
13Indirect evidenceKirkland, WA, United StatesHQ checked Sep 22, 2026201-500254 contacts →

Indirect evidence

“We provide global renewable energy consulting services, focused on empowering clients to navigate the complexities of the energy transition.”

Source: RevenueBase Database · checked Sep 22, 2026
14Indirect evidenceCarlsbad, CA, United StatesHQ checked Sep 22, 2026201-500244 contacts →

Indirect evidence

“rethinkenergy BayWa r.e is a leading global renewable energy company committed to delivering best-in-class projects, services and solutions.”

Source: RevenueBase Database · checked Sep 22, 2026
15Partial evidenceFairfax, VA, United StatesHQ checked Sep 22, 2026201-500214 contacts →

Partial evidence

“PEG presents a comprehensive capacity for the evaluation and understanding of a broad base of energy and environmental sustainability related programs, policies and initiatives.”

Source: RevenueBase Database · checked Sep 22, 2026
16Indirect evidenceHalf Moon Bay, CA, United StatesHQ checked Sep 22, 2026201-500183 contacts →

Indirect evidence

“Resource Innovations now combined with Nexant is a substantially woman-owned, woman-led energy consulting firm dedicated to creating equal access to clean resources through…”

Source: RevenueBase Database · checked Sep 22, 2026
17Partial evidenceScottsdale, AZ, United StatesHQ checked Sep 22, 2026201-500172 contacts →

Partial evidence

“Canacre is an infrastructure development consultant specializing in project management, land acquisition, environment, GIS analysis, data management, web-based mapping, community…”

Source: RevenueBase Database · checked Sep 22, 2026
18Partial evidenceVancouver, WA, United StatesHQ checked Sep 22, 202651-200166 contacts →

Partial evidence

“We’re consultants in energy, public works and land development, and we’re an array of technical disciplines.”

Source: RevenueBase Database · checked Sep 22, 2026
19Indirect evidenceVienna, VA, United StatesHQ checked Sep 22, 2026201-500161 contacts →

Indirect evidence

“Integrated Business & Technical Consultants Inc.(IBTCI), a U.S.”

Source: RevenueBase Database · checked Sep 22, 2026
20Indirect evidenceSan Francisco, CA, United StatesHQ checked Sep 22, 202651-200141 contacts →

Indirect evidence

“Stok leads organizations to decarbonize now.”

Source: RevenueBase Database · checked Sep 22, 2026
21Strong evidenceManchester, NH, United StatesHQ checked Sep 22, 202651-200137 contacts →

Strong evidence

“Hoyle Tanner provides our clients with integrated engineering designs that utilize sustainable and low impact development principles through innovative strategies and technologies.”

Source: RevenueBase Database · checked Sep 22, 2026
22Indirect evidenceMonroe, OH, United StatesHQ checked Sep 22, 2026201-500134 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 22, 2026
23Indirect evidenceCentennial, CO, United StatesHQ checked Sep 22, 202651-200121 contacts →

Indirect evidence

“Halker Consulting provides custom engineered and configured services in Project Assessment and Planning, Engineering and Design, & Consulting and Implementation Guidance.”

Source: RevenueBase Database · checked Sep 22, 2026
24Partial evidenceGambrills, MD, United StatesHQ checked Sep 22, 2026201-500116 contacts →

Partial evidence

“We make sustainable happen.”

Source: RevenueBase Database · checked Sep 22, 2026
25Partial evidenceSeattle, WA, United StatesHQ checked Sep 22, 202651-200110 contacts →

Partial evidence

“Cascadia Consulting Group is a majority women-owned consulting firm specializing in environmental and sustainability solutions.”

Source: RevenueBase Database · checked Sep 22, 2026

Showing 25 of 1,649 sustainable development firms based in the United States

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Sustainable development firms based in the United States at a glance

As of Sep 22, 2026
38.9%Verified-email coverage
13.6Average contacts per company
1-10Median size (employees)
4.7%Largest-city concentration · New York
Sep 22, 2026Page data refreshed

Companies by employee count

1-10
1,187
11-50
340
51-200
81
201-500
20
501-1,000
5
1,001-5,000
9
5,001-10,000
2

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 1,649 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 sustainable development firms, 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 “sustainable development firms”. 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 sustainable development firms), 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 sustainable development firms, 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, 8,746 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 22, 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 sustainable development firms, 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 sustainable development firms are there based in the United States?

RevenueBase identified 1,649 sustainable development firms 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?

Chemonics International, headquartered in Washington, tops this list with the largest team on record.

Which city has the most sustainable development firms?

New York leads with 78 headquartered companies, followed by Washington (57) and Houston (46).

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 8,746 verified decision-maker contacts tracked across these 1,649 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 22, 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.