Company lists · Data refreshed September 2026

Top 25 Trade association law firms based in Washington, United States

Name: Trade association law 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 29, 2026 215 companies tracked

RevenueBase identified 215 trade association law firms headquartered in Washington, United States as of September 2026 and tracks 7,990 professional contacts across them, including 5,220 with verified work emails. Across the United States, Washington is the largest hub for this category.

This list covers trade association law 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 29, 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 29, 2026 86% judged on-target in blind review

215Companies

7,990Contacts tracked

5,220Verified emails

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The 25 largest trade association law firms based in Washington, United States

Ranked by team size

Top 25 of 215 trade association law firms based in Washington, United States, ranked by team size, largest first. Data refreshed Sep 29, 2026. RevenueBase Smart Search rates how each company's information relates to trade association law 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	Arnold & Porter	Indirect evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	1,001-5,000	2,333 contacts →
	Indirect evidence “Arnold & Porter combines sophisticated regulatory, litigation, and transactional capabilities to resolve clients’ most complex issues.” Source: RevenueBase Database · checked Sep 29, 2026
2	Venable LLP	Partial evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	1,001-5,000	1,790 contacts →
	Partial evidence “Committed to Your Success – As a law firm of more than 900 professionals, Venable delivers legal services globally in every area of regulatory compliance, government affairs…” Source: RevenueBase Database · checked Sep 29, 2026
3	Wiley Rein LLP	Indirect evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	501-1,000	576 contacts →
	Indirect evidence “Founded in 1983, Wiley is a dominant presence in the nation’s capital.” Source: RevenueBase Database · checked Sep 29, 2026
4	Keller And Heckman LLP	Partial evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	51-200	230 contacts →
	Partial evidence “Keller and Heckman, founded in 1962, has a broad practice in the areas of regulatory law, public policy, and litigation, serving both domestic and international clients.” Source: RevenueBase Database · checked Sep 29, 2026
5	Kellogg, Hansen, Todd, Figel & Frederick Pllc	Indirect evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	51-200	211 contacts →
	Indirect evidence “Kellogg Hansen works in complex trial and appellate litigation.” Source: RevenueBase Database · checked Sep 29, 2026
6	Zuckerman Spaeder LLP	Indirect evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	51-200	155 contacts →
	Indirect evidence “Zuckerman Spaeder LLP is consistently recognized as a leading national litigation boutique.” Source: RevenueBase Database · checked Sep 29, 2026
7	Wilkinson Barker Knauer, LLP	Partial evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	51-200	138 contacts →
	Partial evidence “With offices in Washington, DC, Denver, Colorado, and Austin, Texas, Wilkinson Barker Knauer (WBK) is the nation’s largest stand-alone communications and technology law firm.” Source: RevenueBase Database · checked Sep 29, 2026
8	Jackson & Campbell, P.C	Strong evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	51-200	129 contacts →
	Strong evidence “For more than 130 years, Jackson & Campbell has been the law firm to which local, regional, and national businesses, associations, and Washingtonians turn for skilled and…” Source: RevenueBase Database · checked Sep 29, 2026
9	Hollingsworth LLP	Indirect evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	51-200	112 contacts →
	Indirect evidence “Hollingsworth LLP is among the nation’s leading litigation firms.” Source: RevenueBase Database · checked Sep 29, 2026
10	Powers LAW	Partial evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	51-200	101 contacts →
	Partial evidence “Powers Pyles Sutter & Verville PC is a Washington, DC-based law firm that began with a strong focus on healthcare law and healthcare policy and has gradually expanded capabilities…” Source: RevenueBase Database · checked Sep 29, 2026
11	Holtzman Vogel	Indirect evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	51-200	80 contacts →
	Indirect evidence “HOLTZMAN VOGEL PROTECTS THE HIGHEST PROFILE VOICES IN BUSINESS, POLITICS AND ADVOCACY For 25 years, Holtzman Vogel has represented Fortune 500 companies, non-profits, high net…” Source: RevenueBase Database · checked Sep 29, 2026
12	Reno & Cavanaugh, Pllc	Partial evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	51-200	73 contacts →
	Partial evidence “Since 1977, Reno & Cavanaugh has been a national law firm dedicated to strengthening communities through strategic use of public and private resources.” Source: RevenueBase Database · checked Sep 29, 2026
13	DOW Lohnes	Indirect evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	201-500	73 contacts →
	Indirect evidence “On January 1, 2014, Dow Lohnes merged with Cooley LLP.” Source: RevenueBase Database · checked Sep 29, 2026
14	Pilieromazza Pllc	Partial evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	51-200	70 contacts →
	Partial evidence “PilieroMazza – a business law firm – serves as a strategic partner to government contractors and commercial businesses from across the United States in numerous industries.” Source: RevenueBase Database · checked Sep 29, 2026
15	HWG LLP	Partial evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	51-200	70 contacts →
	Partial evidence “HWG LLP is a boutique law firm designed to offer clients access to top tier legal talent without unnecessary overhead.” Source: RevenueBase Database · checked Sep 29, 2026
16	Thorn RUN Partners	Indirect evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	51-200	69 contacts →
	Indirect evidence “Established in 2010, Thorn Run Partners is a leading Washington, DC-based government affairs firm whose members are Capitol Hill veterans with over a century’s experience in…” Source: RevenueBase Database · checked Sep 29, 2026
17	Olsson Frank Weeda Terman Matz PC	Partial evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	11-50	49 contacts →
	Partial evidence “Olsson Frank Weeda Terman Matz PC The nation’s premier FDA, USDA, and health care law firm, serving clients before federal agencies, courts, and Congress.” Source: RevenueBase Database · checked Sep 29, 2026
18	Conn Maciel Carey LLP	Partial evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	11-50	46 contacts →
	Partial evidence “Conn Maciel Carey LLP is a boutique law firm focused on Labor & Employment, Workplace Safety - OSHA/MSHA, and Litigation.” Source: RevenueBase Database · checked Sep 29, 2026
19	Bergeson & Campbell, P.C	Indirect evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	11-50	40 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 29, 2026
20	Cooper & Kirk Pllc	Indirect evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	11-50	38 contacts →
	Indirect evidence “Cooper & Kirk is a litigation boutique specializing in commercial, regulatory, and constitutional disputes in both federal and state courts.” Source: RevenueBase Database · checked Sep 29, 2026
21	Tiber Hudson LLC	Partial evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	11-50	36 contacts →
	Partial evidence “Tiber Hudson LLC is a boutique law firm focused in providing legal services including complex commercial litigation, complex commercial transactions, corporate structure and…” Source: RevenueBase Database · checked Sep 29, 2026
22	Tiber Creek Group	Indirect evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	11-50	35 contacts →
	Indirect evidence “Tiber Creek Group is a premier, bipartisan government relations firm delivering custom policy solutions and strategies for industry leaders.” Source: RevenueBase Database · checked Sep 29, 2026
23	O'donoghue & O'donoghue LLP	Partial evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	11-50	35 contacts →
	Partial evidence “O'Donoghue & O'Donoghue LLP is one of the largest and oldest union-side law firms in the United States, with offices in Washington, D.C, Philadelphia, Pennsylvania, and Annapolis…” Source: RevenueBase Database · checked Sep 29, 2026
24	Continental Strategy	Indirect evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	11-50	35 contacts →
	Indirect evidence “Continental Strategy is a government relations firm with offices in Washington D.C, Tallahassee, Miami, Jacksonville, and Latin America.” Source: RevenueBase Database · checked Sep 29, 2026
25	Rule Garza Howley LLP	Indirect evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	11-50	34 contacts →
	Indirect evidence “Rule Garza Howley LLP provides sophisticated antitrust advice and representation, drawing on a proven track record of more than four decades of successful outcomes with the DOJ…” Source: RevenueBase Database · checked Sep 29, 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: trade association law 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 trade association law firms.
Partial evidence: Its own public description names part of trade association law firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name trade association law 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 215 trade association law firms based in Washington, United States

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Trade association law firms based in Washington, United States at a glance

As of Sep 29, 2026

65.3%Verified-email coverage

37.2Average contacts per company

1-10Median size (employees)

Sep 29, 2026Page data refreshed

Companies by employee count

1-10

135

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 215 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 trade association law 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 “trade association law 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 trade association law 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 trade association law 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, 5,220 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 29, 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.

Trade association law 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 trade association law 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 trade association law firms are there based in Washington, United States?

RevenueBase identified 215 trade association law 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?

Arnold & Porter, headquartered in Washington, tops this list with the largest team on record.

Which city in the United States has the most trade association law firms?

Washington leads the United States with 215 headquartered companies, followed by New York (194) and Chicago (129).

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 5,220 verified decision-maker contacts tracked across these 215 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 29, 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.