Company lists · Data refreshed September 2026

Top 25 Environmental sustainability consulting firms based in Washington, United States

Name: Environmental sustainability consulting firms based in Washington, United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 21, 2026 96 companies tracked

RevenueBase identified 96 environmental sustainability consulting firms headquartered in Washington, United States as of September 2026 and tracks 879 professional contacts across them, including 486 with verified work emails. New York is the largest hub.

This list covers environmental sustainability consulting firms headquartered in Washington, 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

96Companies

879Contacts tracked

486Verified emails

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The 25 largest environmental sustainability consulting firms based in Washington, United States

Ranked by team size

Top 25 of 96 environmental sustainability consulting firms based in Washington, United States, ranked by team size, largest first. Data refreshed Sep 21, 2026. RevenueBase Smart Search rates how each company's information relates to environmental sustainability consulting 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.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Beveridge & Diamond PC	Indirect evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	201-500	328 contacts →
	Indirect evidence “Beveridge & Diamond’s 170+ lawyers in 7 U.S.” Source: RevenueBase Database · checked Sep 21, 2026
2	Peer Consultants, P.C	Indirect evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	51-200	71 contacts →
	Indirect evidence “In 1978, PEER was established under Dr.” Source: RevenueBase Database · checked Sep 21, 2026
3	Baumann Consulting	Partial evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	51-200	63 contacts →
	Partial evidence “Baumann Consulting is driven to deliver solutions for a carbon-neutral real estate industry.” Source: RevenueBase Database · checked Sep 21, 2026
4	Northbridge	Partial evidence	Washington, United StatesHQ checked Sep 21, 2026	11-50	24 contacts →
	Partial evidence “At Northbridge, we provide our clients with the tools and expertise to help solve complex financial, policy, and environmental challenges.” Source: RevenueBase Database · checked Sep 21, 2026
5	North Arrow, INC	Indirect evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	11-50	22 contacts →
	Indirect evidence “DUNS Number: 08-001-8268 CAGE Code: 7GN69 SBA Certified Small Business District of Columbia Certified Business Enterprise (CBE) Metropolitan Washington Airports Authority Local…” Source: RevenueBase Database · checked Sep 21, 2026
6	The Clark Group LLC	Strong evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	11-50	19 contacts →
	Strong evidence “The Clark Group is an environmental policy consulting firm that provides a broad range of services to government, private and nonprofit clients.” Source: RevenueBase Database · checked Sep 21, 2026
7	Amis Patel Brewer	Partial evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	1-10	18 contacts →
	Partial evidence “Amis, Patel & Brewer, LLP is a boutique law firm focused on providing legal services to the renewable energy and sustainability sectors.” Source: RevenueBase Database · checked Sep 21, 2026
8	E&w LAW	Partial evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	11-50	18 contacts →
	Partial evidence “At Earth & Water, we are more than lawyers – we’re strategic advisors with unique experience who advance our clients’ interests across a broad range of environmental and business…” Source: RevenueBase Database · checked Sep 21, 2026
9	Numark Associates, INC	Indirect evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	11-50	15 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 21, 2026
10	Co2efficient	Indirect evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	1-10	14 contacts →
	Indirect evidence “CO2EFFICIENT LLC (COEFFICIENT) was founded in 2017 as a mission-focused Washington, D.C.” Source: RevenueBase Database · checked Sep 21, 2026
11	Sustainable YOU	Strong evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	51-200	14 contacts →
	Strong evidence “Sustainable You is a national strategic consulting firm in solar and sustainability serving residential and small commercial clients with a focus in the DC, Maryland and Virginia…” Source: RevenueBase Database · checked Sep 21, 2026
12	Blackwoods Group	Partial evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	1-10	14 contacts →
	Partial evidence “Blackwoods Group is an agriculture and natural resource consulting firm that provides a variety of services ranging from government relations to development and implementation of…” Source: RevenueBase Database · checked Sep 21, 2026
13	Sustainable Strategies DC	Partial evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	1-10	11 contacts →
	Partial evidence “Sustainable Strategies DC is a government affairs and strategic consulting firm based in Washington, DC, that helps clients secure resources for community revitalization and tools…” Source: RevenueBase Database · checked Sep 21, 2026
14	Green Strategies, INC	Indirect evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	1-10	8 contacts →
	Indirect evidence “Green Strategies Inc.” Source: RevenueBase Database · checked Sep 21, 2026
15	The Climate Board	Indirect evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	11-50	7 contacts →
	Indirect evidence “The Climate Board builds AI-enhanced data products for corporate climate teams, closing the gap between infrequent assessments and real-time risk.” Source: RevenueBase Database · checked Sep 21, 2026
16	Green Capitol	Partial evidence	Washington, United StatesHQ checked Sep 21, 2026	1-10	7 contacts →
	Partial evidence “Green Capitol LLC works on sustainable development policy at the state, federal and international levels, serving clients on agriculture, energy and environment concerns via…” Source: RevenueBase Database · checked Sep 21, 2026
17	Energy Shrink, LLC	Strong evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	1-10	6 contacts →
	Strong evidence “Energy Shrink is an environmental consulting practice specialized in sustainability and energy efficiency in buildings, that is, high-performance or green buildings.” Source: RevenueBase Database · checked Sep 21, 2026
18	38 North Solutions	Partial evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	1-10	5 contacts →
	Partial evidence “38 North Solutions is a boutique consulting firm that provides a suite of business strategy and public policy services to innovative businesses and organizations.” Source: RevenueBase Database · checked Sep 21, 2026
19	ALT Surya	Partial evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	1-10	5 contacts →
	Partial evidence “Alt Surya is a global climate advisory firm, which provides expert consulting services to clients in Asia and North America.” Source: RevenueBase Database · checked Sep 21, 2026
20	Oasis Energy Partners	Strong evidence	Washington, United StatesHQ checked Sep 21, 2026	1-10	5 contacts →
	Strong evidence “OASIS Energy Partners is a full-service consulting and advisory firm at the intersection of energy, environment, and climate.” Source: RevenueBase Database · checked Sep 21, 2026
21	GQS NEW Energy Strategies	Indirect evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	1-10	5 contacts →
	Indirect evidence “Our team leverages deep industry expertise to help you navigate regulatory shifts and seize new opportunities in clean energy.” Source: RevenueBase Database · checked Sep 21, 2026
22	Deborah Brosnan & Associates	Indirect evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	1-10	4 contacts →
	Indirect evidence “Leading and innovative company that finding solutions, bridging gaps and driving positive action for clients and the planet.” Source: RevenueBase Database · checked Sep 21, 2026
23	Lightbox Energy	Partial evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	1-10	4 contacts →
	Partial evidence “Lightbox Energy is an energy and sustainability program management firm.” Source: RevenueBase Database · checked Sep 21, 2026
24	Sustainability Frameworks	Strong evidence	Washington, United StatesHQ checked Sep 21, 2026	1-10	4 contacts →
	Strong evidence “Sustainability Frameworks helps its public and private sector clients develop strategies to manage their environmental and social risks and opportunities, optimize their…” Source: RevenueBase Database · checked Sep 21, 2026
25	JG Global Advisory, LLC	Partial evidence	Washington, DC, United StatesHQ checked Sep 21, 2026	1-10	4 contacts →
	Partial evidence “JG Global Advisory, LLC is a minority, woman-owned small business (WOSB) consultancy providing advisory services and integrated solutions for environmental and international…” Source: RevenueBase Database · checked Sep 21, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: environmental sustainability consulting firms. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names environmental sustainability consulting firms.
Partial evidence: Its own public description names part of environmental sustainability consulting firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name environmental sustainability consulting firms. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 25 of 96 environmental sustainability consulting firms based in Washington, United States

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Environmental sustainability consulting firms based in Washington, United States at a glance

As of Sep 21, 2026

55.3%Verified-email coverage

9.2Average contacts per company

1-10Median size (employees)

246.9%Largest-city concentration · New York

Sep 21, 2026Page data refreshed

Companies by employee count

1-10

11-50

51-200

201-500

Email recency for this list is measured across the whole United States list rather than for Washington, so it is reported there. Company counts and contact totals on this page are exact for Washington, over 96 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 environmental sustainability consulting 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 Washington, United States whose own description of what they do matches “environmental sustainability consulting 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 environmental sustainability consulting 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 environmental sustainability consulting firms, and records with no verified work email. Companies headquartered outside Washington 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, 486 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.

Environmental sustainability consulting firms by metro in the United States

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 environmental sustainability consulting 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 environmental sustainability consulting firms are there based in Washington, United States?

RevenueBase identified 96 environmental sustainability consulting firms headquartered in Washington, 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?

Beveridge & Diamond PC, headquartered in Washington, tops this list with the largest team on record.

Which city has the most environmental sustainability consulting firms?

New York leads with 237 headquartered companies, followed by Houston (131) and Los Angeles (101).

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 486 verified decision-maker contacts tracked across these 96 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.