Company lists · Data refreshed September 2026

Top 25 Environmental nonprofits based in Washington, United States

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

Compiled by the RevenueBase Data Team Data refreshed Sep 19, 2026 195 companies tracked

RevenueBase identified 195 environmental nonprofits headquartered in Washington, United States as of September 2026 and tracks 8,864 professional contacts across them, including 3,005 with verified work emails. Washington is the largest hub.

This list covers environmental nonprofits 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 19, 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 19, 2026 86% judged on-target in blind review

195Companies

8,864Contacts tracked

3,005Verified emails

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The 25 largest environmental nonprofits based in Washington, United States

Ranked by team size

Top 25 of 195 environmental nonprofits based in Washington, United States, ranked by team size, largest first. Data refreshed Sep 19, 2026. RevenueBase Smart Search rates how each company's information relates to environmental nonprofits: 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	World Resources Institute	Indirect evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	1,001-5,000	1,359 contacts →
	Indirect evidence “WRI works to improve people’s lives, protect and restore nature and stabilize the climate.” Source: RevenueBase Database · checked Sep 19, 2026
2	U.S. Green Building Council	Indirect evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	201-500	553 contacts →
	Indirect evidence “The U.S.” Source: RevenueBase Database · checked Sep 19, 2026
3	Clean Water Action	Partial evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	51-200	366 contacts →
	Partial evidence “Since our founding during the campaign to pass the landmark Clean Water Act in 1972, Clean Water Action has worked to win strong health and environmental protections by bringing…” Source: RevenueBase Database · checked Sep 19, 2026
4	IFAW	Indirect evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	201-500	355 contacts →
	Indirect evidence “IFAW explores new ways to improve conditions for animals, people, and the place we call home-and we’ve been leading the way for over 50 years.” Source: RevenueBase Database · checked Sep 19, 2026
5	National Parks Conservation Association	Indirect evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	51-200	303 contacts →
	Indirect evidence “Named a USA Top Workplace in 2023** For a century, National Parks Conservation Association has been a powerful independent voice working to strengthen and protect America's…” Source: RevenueBase Database · checked Sep 19, 2026
6	League Of Conservation Voters	Indirect evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	51-200	218 contacts →
	Indirect evidence “LCV believes our earth is worth fighting for because everyone has a right to clean air, water, and a safe, healthy community.” Source: RevenueBase Database · checked Sep 19, 2026
7	Defenders Of Wildlife	Indirect evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	51-200	202 contacts →
	Indirect evidence “Defenders of Wildlife is dedicated to the protection of all native animals and plants in their natural communities.” Source: RevenueBase Database · checked Sep 19, 2026
8	The Wilderness Society	Indirect evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	51-200	199 contacts →
	Indirect evidence “The Wilderness Society (TWS) is the leading conservation organization working to protect America’s wild places and public lands for the health of local communities, wildlife, and…” Source: RevenueBase Database · checked Sep 19, 2026
9	The International Council On Clean Transportation	Partial evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	51-200	196 contacts →
	Partial evidence “The International Council on Clean Transportation is an independent nonprofit organization founded to provide first-rate, unbiased research and technical and scientific analysis…” Source: RevenueBase Database · checked Sep 19, 2026
10	National Park Foundation	Indirect evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	51-200	157 contacts →
	Indirect evidence “The National Park Foundation works to protect wildlife and park lands, preserve history and culture, educate and engage youth, and connect people everywhere to the wonder of parks.” Source: RevenueBase Database · checked Sep 19, 2026
11	American Rivers	Indirect evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	51-200	147 contacts →
	Indirect evidence “American Rivers protects wild rivers, restores damaged rivers, and conserves clean water for people and nature.” Source: RevenueBase Database · checked Sep 19, 2026
12	earthday.org	Partial evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	11-50	144 contacts →
	Partial evidence “EARTHDAY.ORG’s mission is to diversify, educate and activate the environmental movement worldwide.” Source: RevenueBase Database · checked Sep 19, 2026
13	American Forests	Partial evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	51-200	136 contacts →
	Partial evidence “Founded in 1875, American Forests is the oldest national nonprofit conservation organization in the U.S.” Source: RevenueBase Database · checked Sep 19, 2026
14	Resources For The Future	Partial evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	51-200	135 contacts →
	Partial evidence “Resources for the Future improves environmental, energy, and natural resource decisions through impartial economic research and policy engagement.” Source: RevenueBase Database · checked Sep 19, 2026
15	Earthworks	Strong evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	11-50	126 contacts →
	Strong evidence “EARTHWORKS is a nonprofit organization dedicated to protecting communities and the environment from the impacts of irresponsible mineral and energy development while seeking…” Source: RevenueBase Database · checked Sep 19, 2026
16	Environmental Working Group	Partial evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	51-200	120 contacts →
	Partial evidence “The Environmental Working Group is a non-profit, non-partisan organization dedicated to protecting human health and the environment.” Source: RevenueBase Database · checked Sep 19, 2026
17	American Forest Foundation	Indirect evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	51-200	118 contacts →
	Indirect evidence “The American Forest Foundation (AFF) is a national conservation organization that works to deliver clean water, wildlife habitat, carbon sequestration and storage, and sustainable…” Source: RevenueBase Database · checked Sep 19, 2026
18	Environmental LAW Institute	Partial evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	11-50	102 contacts →
	Partial evidence “The Environmental Law Institute (ELI) makes law work for people, places, and the planet.” Source: RevenueBase Database · checked Sep 19, 2026
19	Greenpeace USA	Indirect evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	51-200	97 contacts →
	Indirect evidence “Founded in 1971, Greenpeace began when a small group of activists sailed from Vancouver to protest nuclear testing at Amchitka, Alaska.” Source: RevenueBase Database · checked Sep 19, 2026
20	Bezos Earth Fund	Indirect evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	11-50	89 contacts →
	Indirect evidence “Built on the belief that Earth is the best planet in the solar system, Jeff Bezos & Lauren Sánchez Bezos have made a $10 billion commitment to protect and restore the natural…” Source: RevenueBase Database · checked Sep 19, 2026
21	Earthecho International	Partial evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	n/a	86 contacts →
	Partial evidence “EarthEcho International is a nonprofit 501c3 organization founded in 2005 by siblings Philippe and Alexandra Cousteau in honor of their father Philippe Cousteau Sr, son of the…” Source: RevenueBase Database · checked Sep 19, 2026
22	Delterra	Partial evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	51-200	83 contacts →
	Partial evidence “Delterra is an environmental NGO, originally founded by McKinsey & Company.” Source: RevenueBase Database · checked Sep 19, 2026
23	Earthrights International	Partial evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	11-50	82 contacts →
	Partial evidence “EarthRights International is a nongovernmental, nonprofit organization that combines the power of law and the power of people in defense of earth rights.” Source: RevenueBase Database · checked Sep 19, 2026
24	Forest Trends Association	Partial evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	11-50	76 contacts →
	Partial evidence “Forest Trends works to conserve forests and other ecosystems through the creation and wide adoption of a range of environmental finance, market, and other payment and incentive…” Source: RevenueBase Database · checked Sep 19, 2026
25	Center For International Environmental LAW Ciel	Partial evidence	Washington, DC, United StatesHQ checked Sep 19, 2026	51-200	74 contacts →
	Partial evidence “The Center for International Environmental Law (CIEL) uses the power of the law to protect the environment, promote human health, and ensure a just and sustainable society.” Source: RevenueBase Database · checked Sep 19, 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 nonprofits. 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 nonprofits.
Partial evidence: Its own public description names part of environmental nonprofits, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name environmental nonprofits. 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 195 environmental nonprofits based in Washington, United States

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Environmental nonprofits based in Washington, United States at a glance

As of Sep 19, 2026

33.9%Verified-email coverage

45.5Average contacts per company

1-10Median size (employees)

100.0%Largest-city concentration · Washington

Sep 19, 2026Page data refreshed

Companies by employee count

1-10

100

11-50

51-200

201-500

501-1,000

1,001-5,000

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 195 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 nonprofits, 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 nonprofits”. 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 nonprofits), 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 nonprofits, 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, 3,005 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 19, 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 nonprofits 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 nonprofits, 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 nonprofits are there based in Washington, United States?

RevenueBase identified 195 environmental nonprofits 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?

World Resources Institute, headquartered in Washington, tops this list with the largest team on record.

Which city has the most environmental nonprofits?

Washington leads with 195 headquartered companies, followed by New York (194) and San Francisco (126).

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 3,005 verified decision-maker contacts tracked across these 195 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 19, 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.