Company lists · Data refreshed September 2026

Top 25 Environmental research and advocacy organizations based in the United States

Name: Environmental research and advocacy organizations 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 1,865 companies tracked

RevenueBase identified 1,865 company matches for environmental research and advocacy organizations associated with the United States as of September 2026 and tracks 44,481 professional contacts across them, including 17,505 with verified work emails. Washington is the largest hub.

This list covers company matches for environmental research and advocacy organizations 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 September 19, 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 Sep 19, 2026 How this list was built

1,865Companies

44,481Contacts tracked

17,505Verified emails

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The 25 largest environmental research and advocacy organizations based in the United States

Ranked by team size

Top 25 of 1,865 company matches for environmental research and advocacy organizations based in the United States, ordered by professional contacts tracked in RevenueBase, largest first. Recorded Sep 19, 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	The Nature Conservancy	Exact match	Arlington, VA, United StatesHQ recorded Sep 19, 2026	5,001-10,000	6,526 contacts →
	Exact match “Air, water, food, shelter, income: nature sustains every aspect of our lives.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
2	Conservation International	Exact match	Arlington, VA, United StatesHQ recorded Sep 19, 2026	501-1,000	1,560 contacts →
	Exact match “Since 1987, Conservation International has worked to spotlight and secure the critical benefits that nature provides to humanity.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
3	World Resources Institute	Exact match	Washington, DC, United StatesHQ recorded Sep 19, 2026	1,001-5,000	1,359 contacts →
	Exact match “WRI works to improve people’s lives, protect and restore nature and stabilize the climate.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
4	Environmental Defense Fund	Exact match	New York, NY, United StatesHQ recorded Sep 19, 2026	1,001-5,000	1,352 contacts →
	Exact match “We are Environmental Defense Fund, a leading environmental nonprofit focused on stabilizing the climate while helping build strong and healthy communities.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
5	Sierra Club	Exact match	Oakland, CA, United StatesHQ recorded Sep 19, 2026	501-1,000	1,069 contacts →
	Exact match “At the Sierra Club, we believe in the power of togetherness.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
6	Natural Resources Defense Council Nrdc	Exact match	New York, NY, United StatesHQ recorded Sep 19, 2026	501-1,000	942 contacts →
	Exact match “NRDC is the nation's most effective environmental action organization.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
7	Earthjustice	Exact match	San Francisco, United StatesHQ recorded Sep 19, 2026	501-1,000	672 contacts →
	Exact match “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…” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
8	PETA	Exact match	Norfolk, VA, United StatesHQ recorded Sep 19, 2026	201-500	592 contacts →
	Exact match “People for the Ethical Treatment of Animals (PETA) entities have more than 10.4 million members and supporters globally, and PETA U.S.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
9	Mass Audubon	Exact match	Lincoln, MA, United StatesHQ recorded Sep 19, 2026	201-500	554 contacts →
	Exact match “Mass Audubon is the largest nature-based conservation organization in New England.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
10	Western Ecosystems Technology, Inc. West	Exact match	Cheyenne, WY, United StatesHQ recorded Sep 19, 2026	201-500	408 contacts →
	Exact match “WEST provides environmental and statistical consulting services and contract research nationally and internationally to industry, government, and private organizations.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
11	RARE	Exact match	Arlington, VA, United StatesHQ recorded Sep 19, 2026	51-200	368 contacts →
	Exact match “Rare is a global leader in driving social change for people and nature.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
12	Clean Water Action	Exact match	Washington, DC, United StatesHQ recorded Sep 19, 2026	51-200	366 contacts →
	Exact match “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…” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
13	Lynker	Exact match	Leesburg, VA, United StatesHQ recorded Sep 19, 2026	501-1,000	363 contacts →
	Exact match “Lynker delivers innovative solutions to support global environmental security and economic prosperity as a trusted partner to governments, communities, and industry.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
14	Chesapeake BAY Foundation	Exact match	Annapolis, MD, United StatesHQ recorded Sep 19, 2026	51-200	312 contacts →
	Exact match “The Chesapeake Bay Foundation (CBF) fights for bold and creative solutions to the pollution that plagues the Bay and its tributaries.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
15	GSI Environmental INC	Exact match	Houston, TX, United StatesHQ recorded Sep 19, 2026	201-500	259 contacts →
	Exact match “GSI Environmental, Inc.(GSI), is an environmental engineering and science consulting firm committed to measuring, analyzing, and solving complex environmental problems around the…” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
16	Union Of Concerned Scientists	Exact match	Cambridge, MA, United StatesHQ recorded Sep 19, 2026	201-500	254 contacts →
	Exact match “Our mission is to use rigorous, independent science to solve our planet's most pressing problems.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
17	Ceres, INC	Exact match	Boston, MA, United StatesHQ recorded Sep 19, 2026	51-200	241 contacts →
	Exact match “Ceres is a nonprofit advocacy organization working to accelerate the transition to a cleaner, more just, and resilient world.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
18	Seaside Sustainability	Exact match	Gloucester, MA, United StatesHQ recorded Sep 19, 2026	51-200	240 contacts →
	Exact match “Seaside Sustainability is a nationally recognized, award-winning 501(c)3 charitable organization dedicated to community engagement, education and environmental conservation.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
19	The Conservation Fund	Exact match	Arlington, VA, United StatesHQ recorded Sep 19, 2026	201-500	224 contacts →
	Exact match “We are in the business of conservation, creating innovative solutions that drive nature-based action for climate protection, sustainable economies and vibrant communities.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
20	Center For Biological Diversity	Exact match	Tucson, AZ, United StatesHQ recorded Sep 19, 2026	51-200	219 contacts →
	Exact match “At the Center for Biological Diversity, we believe that the welfare of human beings is deeply linked to nature, to the existence in our world of a vast diversity of wild animals…” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
21	League Of Conservation Voters	Exact match	Washington, DC, United StatesHQ recorded Sep 19, 2026	51-200	218 contacts →
	Exact match “LCV believes our earth is worth fighting for because everyone has a right to clean air, water, and a safe, healthy community.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
22	Energy & Environmental Research Center	Exact match	Grand Forks, ND, United StatesHQ recorded Sep 19, 2026	201-500	213 contacts →
	Exact match “The Energy & Environmental Research Center (EERC) is recognized as one of the world's leading developers of cleaner, more efficient energy to power the world and environmental…” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
23	Conservation Corps Minnesota & Iowa	Exact match	St. Paul, MN, United StatesHQ recorded Sep 19, 2026	201-500	207 contacts →
	Exact match “At Conservation Corps Minnesota & Iowa, youth and young adults grow as environmental stewards and leaders while giving back to the community through meaningful service.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
24	Defenders Of Wildlife	Exact match	Washington, DC, United StatesHQ recorded Sep 19, 2026	51-200	202 contacts →
	Exact match “Defenders of Wildlife is dedicated to the protection of all native animals and plants in their natural communities.” Recorded in the RevenueBase company graph · Sep 19, 2026 · View company records in RevenueBase
25	The Wilderness Society	Exact match	Washington, DC, United StatesHQ recorded Sep 19, 2026	51-200	199 contacts →
	Exact match “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…” Recorded in the RevenueBase company graph · Sep 19, 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 “environmental research and advocacy organizations”. 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 1,865 environmental research and advocacy organizations based in the United States

See the full list, filter by size, metro and specialty, and access 17,505 tracked professional contacts with verified work emails. Direct dials are available where recorded.

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Environmental research and advocacy organizations based in the United States at a glance

As of Sep 19, 2026

39.4%Verified-email coverage

23.9Average contacts per company

1-10Median size (employees)

6.3%Largest-city concentration · Washington

Sep 19, 2026Page data refreshed

Companies by employee count

1-10

1,184

11-50

505

51-200

117

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 1,865 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 “environmental research and advocacy organizations” 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 17,505 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 September 19, 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.

Environmental research and advocacy organizations 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 “environmental research and advocacy organizations”; each Exact match badge shows search membership, not an individual similarity or quality score.

How many environmental research and advocacy organizations are there based in the United States?

RevenueBase identified 1,865 company matches for environmental research and advocacy organizations associated with the United States as of September 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?

The Nature Conservancy tops the displayed preview by professional contacts tracked in RevenueBase. Recorded headquarters appear in the company rows.

Which city has the most environmental research and advocacy organizations?

Washington leads with 118 company records, followed by New York (77) and San Francisco (42).

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 17,505 professional contacts with verified work emails tracked across these 1,865 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 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 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.