Company lists · Data refreshed September 2026

Top 25 Environmental nonprofits based in the United States

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

Compiled by the RevenueBase Data Team Data refreshed Sep 19, 2026 5,243 companies tracked

RevenueBase identified 5,243 environmental nonprofits headquartered in the United States as of September 2026 and tracks 80,760 professional contacts across them, including 28,852 with verified work emails. Washington is the largest hub.

This list covers environmental nonprofits 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 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

5,243Companies

80,760Contacts tracked

28,852Verified emails

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The 25 largest environmental nonprofits based in the United States

Ranked by team size

Top 25 of 5,243 environmental nonprofits based in the 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	The Nature Conservancy	Indirect evidence	Arlington, VA, United StatesHQ checked Sep 19, 2026	5,001-10,000	6,526 contacts →
	Indirect evidence “Air, water, food, shelter, income: nature sustains every aspect of our lives.” Source: RevenueBase Database · checked Sep 19, 2026
2	Conservation International	Indirect evidence	Arlington, VA, United StatesHQ checked Sep 19, 2026	501-1,000	1,560 contacts →
	Indirect evidence “Since 1987, Conservation International has worked to spotlight and secure the critical benefits that nature provides to humanity.” Source: RevenueBase Database · checked Sep 19, 2026
3	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
4	Environmental Defense Fund	Strong evidence	New York, NY, United StatesHQ checked Sep 19, 2026	1,001-5,000	1,352 contacts →
	Strong evidence “We are Environmental Defense Fund, a leading environmental nonprofit focused on stabilizing the climate while helping build strong and healthy communities.” Source: RevenueBase Database · checked Sep 19, 2026
5	Casa Familiar	Indirect evidence	Albuquerque, NM, United StatesHQ checked Sep 19, 2026	n/a	1,132 contacts →
	Indirect evidence “Casa Familiar is a primary/secondary education company based out of 501 Atrisco Dr Sw, Albuquerque, New Mexico, United States.” Source: RevenueBase Database · checked Sep 19, 2026
6	Sierra Club	Indirect evidence	Oakland, CA, United StatesHQ checked Sep 19, 2026	501-1,000	1,069 contacts →
	Indirect evidence “At the Sierra Club, we believe in the power of togetherness.” Source: RevenueBase Database · checked Sep 19, 2026
7	Natural Resources Defense Council Nrdc	Partial evidence	New York, NY, United StatesHQ checked Sep 19, 2026	501-1,000	942 contacts →
	Partial evidence “NRDC is the nation's most effective environmental action organization.” Source: RevenueBase Database · checked Sep 19, 2026
8	Student Conservation Association	Partial evidence	Arlington, VA, United StatesHQ checked Sep 19, 2026	201-500	795 contacts →
	Partial evidence “The Student Conservation Association (SCA) is the largest provider of hands-on environmental conservation programs for youth and adults.” Source: RevenueBase Database · checked Sep 19, 2026
9	Monterey BAY Aquarium	Partial evidence	Monterey, CA, United StatesHQ checked Sep 19, 2026	501-1,000	738 contacts →
	Partial evidence “The mission of the nonprofit Monterey Bay Aquarium is to inspire conservation of the ocean.” Source: RevenueBase Database · checked Sep 19, 2026
10	Earthjustice	Indirect evidence	San Francisco, United StatesHQ checked Sep 19, 2026	501-1,000	672 contacts →
	Indirect evidence “Earthjustice is a non-profit public interest law organization dedicated to protecting the magnificent places, natural resources, and wildlife of this earth, and to defending the…” Source: RevenueBase Database · checked Sep 19, 2026
11	National Wildlife Federation	Indirect evidence	Reston, VA, United StatesHQ checked Sep 19, 2026	201-500	585 contacts →
	Indirect evidence “As America's largest non-profit conservation organization, the National Wildlife Federation works closely with those who span the social and political spectrum, but who are…” Source: RevenueBase Database · checked Sep 19, 2026
12	Mass Audubon	Indirect evidence	Lincoln, MA, United StatesHQ checked Sep 19, 2026	201-500	554 contacts →
	Indirect evidence “Mass Audubon is the largest nature-based conservation organization in New England.” Source: RevenueBase Database · checked Sep 19, 2026
13	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
14	Trust For Public Land	Partial evidence	San Francisco, CA, United StatesHQ checked Sep 19, 2026	201-500	531 contacts →
	Partial evidence “Trust for Public Land (TPL) is a national nonprofit that works to connect everyone to the benefits and joys of the outdoors.” Source: RevenueBase Database · checked Sep 19, 2026
15	The Providencia Group	Indirect evidence	Ashburn, VA, United StatesHQ checked Sep 19, 2026	201-500	444 contacts →
	Indirect evidence “At Providencia we are focused on positively impacting the communities where we operate, the lives of vulnerable and underserved populations around the world, and the health of our…” Source: RevenueBase Database · checked Sep 19, 2026
16	Shimano	Indirect evidence	Irvine, CA, United StatesHQ checked Sep 19, 2026	201-500	382 contacts →
	Indirect evidence “To promote health and happiness through the enjoyment of nature and the world around us” Source: RevenueBase Database · checked Sep 19, 2026
17	Appalachian Mountain Club	Indirect evidence	Boston, MA, United StatesHQ checked Sep 19, 2026	201-500	378 contacts →
	Indirect evidence “The mission of the Appalachian Mountain Club is to foster the protection, enjoyment, and understanding of the outdoors.” Source: RevenueBase Database · checked Sep 19, 2026
18	RARE	Indirect evidence	Arlington, VA, United StatesHQ checked Sep 19, 2026	51-200	368 contacts →
	Indirect evidence “Rare is a global leader in driving social change for people and nature.” Source: RevenueBase Database · checked Sep 19, 2026
19	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
20	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
21	Golden Gate National Parks Conservancy	Partial evidence	San Francisco, CA, United StatesHQ checked Sep 19, 2026	201-500	315 contacts →
	Partial evidence “Since 1981, the Golden Gate National Parks Conservancy (Parks Conservancy) has served as the nonprofit partner of the National Park Service, collaborating with the Presidio Trust…” Source: RevenueBase Database · checked Sep 19, 2026
22	Chesapeake BAY Foundation	Indirect evidence	Annapolis, MD, United StatesHQ checked Sep 19, 2026	51-200	312 contacts →
	Indirect evidence “The Chesapeake Bay Foundation (CBF) fights for bold and creative solutions to the pollution that plagues the Bay and its tributaries.” Source: RevenueBase Database · checked Sep 19, 2026
23	Whitewater	Partial evidence	Charlotte, NC, United StatesHQ checked Sep 19, 2026	501-1,000	312 contacts →
	Partial evidence “Whitewater is a 501(c)(3) nonprofit and outdoor lifestyle brand that facilitates outdoor access by lowering barriers and inspiring people to get outside.” Source: RevenueBase Database · checked Sep 19, 2026
24	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
25	Union Of Concerned Scientists	Indirect evidence	Cambridge, MA, United StatesHQ checked Sep 19, 2026	201-500	254 contacts →
	Indirect evidence “Our mission is to use rigorous, independent science to solve our planet's most pressing problems.” 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 5,243 environmental nonprofits based in the United States

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Environmental nonprofits based in the United States at a glance

As of Sep 19, 2026

35.7%Verified-email coverage

15.4Average contacts per company

1-10Median size (employees)

3.7%Largest-city concentration · Washington

Sep 19, 2026Page data refreshed

Companies by employee count

1-10

3,659

11-50

1,223

51-200

259

201-500

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 5,243 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 the 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 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, 28,852 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

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 the United States?

RevenueBase identified 5,243 environmental nonprofits 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?

The Nature Conservancy, headquartered in Arlington, 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 28,852 verified decision-maker contacts tracked across these 5,243 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.