Company lists · Data refreshed September 2026

Top 25 Ecological consulting firms based in Washington, United States

Name: Ecological 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 12, 2026 49 companies tracked

RevenueBase identified 49 ecological consulting firms headquartered in Washington, United States as of September 2026 and tracks 631 professional contacts across them, including 386 with verified work emails and 344 with mobile numbers. Houston is the largest hub.

This list covers ecological 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 12, 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 12, 2026 86% judged on-target in blind review

49Companies

631Contacts tracked

386Verified emails

344Mobile numbers

Explore this list → Free signup · no credit card · 500 free credits

The 25 largest ecological consulting firms based in Washington, United States

Ranked by team size

Top 25 of 49 ecological consulting firms based in Washington, United States, ranked by team size, largest first. Data refreshed Sep 12, 2026. RevenueBase Smart Search rates how each company's information relates to ecological 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 12, 2026	201-500	328 contacts →
	Indirect evidence “Beveridge & Diamond’s 170+ lawyers in 7 U.S.” Source: RevenueBase Database · checked Sep 12, 2026
2	Peer Consultants, P.C	Indirect evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	51-200	71 contacts →
	Indirect evidence “In 1978, PEER was established under Dr.” Source: RevenueBase Database · checked Sep 12, 2026
3	Northbridge	Indirect evidence	Washington, United StatesHQ checked Sep 12, 2026	11-50	24 contacts →
	Indirect 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 12, 2026
4	The Clark Group LLC	Partial evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	11-50	19 contacts →
	Partial 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 12, 2026
5	Dawson & Associates	Indirect evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	11-50	16 contacts →
	Indirect evidence “Dawson & Associates is the nation’s premier firm for resolving complex challenges involving Federal water and environmental policies.” Source: RevenueBase Database · checked Sep 12, 2026
6	Numark Associates, INC	Indirect evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	11-50	15 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 12, 2026
7	Toxservices LLC	Partial evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	11-50	14 contacts →
	Partial evidence “ToxServices is a scientific consulting firm providing with more than a decade of expertise in toxicology, risk assessment, comparative hazard assessment, and the application of…” Source: RevenueBase Database · checked Sep 12, 2026
8	Blackwoods Group	Partial evidence	Washington, DC, United StatesHQ checked Sep 12, 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 12, 2026
9	Sustainable Strategies DC	Partial evidence	Washington, DC, United StatesHQ checked Sep 12, 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 12, 2026
10	TSG Consulting	Indirect evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	51-200	11 contacts →
	Indirect evidence “For over 30 years, TSG has provided companies around the world with regulatory guidance and scientific expertise.” Source: RevenueBase Database · checked Sep 12, 2026
11	TWW	Indirect evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	11-50	10 contacts →
	Indirect evidence “The Wright Way Enterprises (TWW) is certified as an SBA 8(a) and HUBZone small business and DC Certified Business Enterprise (CBE), stewarding organizations in addressing the…” Source: RevenueBase Database · checked Sep 12, 2026
12	Green Strategies, INC	Indirect evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	1-10	8 contacts →
	Indirect evidence “Green Strategies Inc.” Source: RevenueBase Database · checked Sep 12, 2026
13	Designgreen, LLC	Partial evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	1-10	7 contacts →
	Partial evidence “Designgreen, LLC is a woman-owned engineering firm located in the District of Columbia offering professional consulting and technical support services for small and large projects…” Source: RevenueBase Database · checked Sep 12, 2026
14	Green Capitol	Indirect evidence	Washington, United StatesHQ checked Sep 12, 2026	1-10	7 contacts →
	Indirect 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 12, 2026
15	Energy Shrink, LLC	Partial evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	1-10	6 contacts →
	Partial 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 12, 2026
16	Natural Resource Results, LLC	Partial evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	1-10	6 contacts →
	Partial evidence “Natural Resource Results, LLC is a leader in lobbying and government affairs consulting dedicated to principled advocacy, responsive consulting, and timely results for each client.” Source: RevenueBase Database · checked Sep 12, 2026
17	Washington Occupational Health Associates	Partial evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	11-50	5 contacts →
	Partial evidence “For over 30 years, Washington Occupational Health Associates (WOHA) has been the leading provider of expert occupational, environmental, and public health consulting services to…” Source: RevenueBase Database · checked Sep 12, 2026
18	Natural Resources Design, INC	Indirect evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	1-10	5 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 12, 2026
19	Deborah Brosnan & Associates	Indirect evidence	Washington, DC, United StatesHQ checked Sep 12, 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 12, 2026
20	JG Global Advisory, LLC	Indirect evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	1-10	4 contacts →
	Indirect 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 12, 2026
21	Strategic Conservation Solutions, LLC	Partial evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	1-10	3 contacts →
	Partial evidence “Strategic Conservation Solutions, LLC (SCS) is a specialized consulting firm providing advocacy, visioning and strategic positioning to firms and associations in the areas of…” Source: RevenueBase Database · checked Sep 12, 2026
22	Warwick Group Consultants, LLC	Partial evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	1-10	3 contacts →
	Partial evidence “Warwick Group Consultants is the Nation's premier consulting firm for local governments with coastal projects involving beach nourishment, dredging, aquatic ecosystem restoration…” Source: RevenueBase Database · checked Sep 12, 2026
23	Greening Urban LLC	Indirect evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	1-10	3 contacts →
	Indirect evidence “Greening Urban is a civil engineering firm with built projects in Washington, D.C; Maryland; and Virginia.” Source: RevenueBase Database · checked Sep 12, 2026
24	Ardeidae Group	Indirect evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	1-10	2 contacts →
	Indirect evidence “Strategic advisory services for the triple bottom line.” Source: RevenueBase Database · checked Sep 12, 2026
25	Watershed Results LLC	Indirect evidence	Washington, DC, United StatesHQ checked Sep 12, 2026	1-10	2 contacts →
	Indirect evidence “Greg Schildwachter is a professional conservationist serving businesses and mission-organizations with his credentials in wildlife science and skill as a lobbyist and consultant.” Source: RevenueBase Database · checked Sep 12, 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: ecological 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 ecological consulting firms.
Partial evidence: Its own public description names part of ecological consulting firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name ecological 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 49 ecological consulting firms based in Washington, United States

See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 386 reachable decision-makers.

Free signup · no credit card

View the full list →

Ecological consulting firms based in Washington, United States at a glance

As of Sep 12, 2026

61.2%Verified-email coverage

54.5%Mobile-number coverage

12.9Average contacts per company

1-10Median size (employees)

157.1%Largest-city concentration · Houston

Sep 12, 2026Page data refreshed

Companies by employee count

1-10

11-50

51-200

201-500

Freshness & accuracy

How recently the business emails were verified and the company information checked

Email last verified

Median 14.0d

3300–30

5631–60

061–90

090–180

0180+

Company record updated

Median 56.0d

00–30

33731–60

22661–90

4490–180

24180+

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 ecological 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 “ecological 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 ecological 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 ecological 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, 386 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 12, 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.

Ecological consulting firms by metro in the United States

Ecological consulting firms in Houston77
Ecological consulting firms in New York70
Ecological consulting firms in Portland64
Ecological consulting firms in Seattle57
Ecological consulting firms in Washington52
Ecological consulting firms in Chicago48
Ecological consulting firms in San Diego47

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 ecological 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 ecological consulting firms are there based in Washington, United States?

RevenueBase identified 49 ecological 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 ecological consulting firms?

Houston leads with 77 headquartered companies, followed by New York (70) and Portland (64).

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 386 verified decision-maker contacts tracked across these 49 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 12, 2026.

Ready to reach these companies? Verified emails and direct dials for all 49 ecological consulting firms based in Washington, United States. Start with a free account, no credit card.

Download this list →

Related lists

Ecological consulting firms by geography

Browse the directory

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.