Company lists · Data refreshed September 2026
Top 25 501c3 law firms based in Washington, United States
RevenueBase identified 45 501c3 law firms headquartered in Washington, United States as of September 2026 and tracks 491 professional contacts across them, including 268 with verified work emails and 259 with mobile numbers. Across the United States, New York is the largest hub for this category (36 companies); Washington follows with 32.
This list covers 501c3 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 27, 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.
The 25 largest 501c3 law firms based in Washington, United States
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 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 27, 2026Thanks. The Data Team will review it. | |||||
| 2 | 50 contacts → | ||||
Partial evidence “Ivins, Phillips & Barker is exclusively engaged in the practice of federal tax, benefits and compensation, and estate and gift tax law.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 3 | 46 contacts → | ||||
Indirect evidence “The D.C.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 4 | 28 contacts → | ||||
Partial evidence “DC Affordable Law Firm ("DCALF") is a nonprofit law firm in Washington, DC providing accessible and affordable family law, immigration, and probate legal services to hardworking…” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 5 | 27 contacts → | ||||
Partial evidence “Webster, Chamberlain & Bean, LLP is the leading law firm in the United States specializing in the provision of a full range of legal services to tax-exempt organizations.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 6 | 26 contacts → | ||||
Indirect evidence “Trister, Ross, Schadler & Gold, PLLC combines personalized client service with decades of broad experience and specialized legal expertise.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 7 | 18 contacts → | ||||
Indirect evidence “Silver, Freedman, Taff & Tiernan LLP, is a preeminent legal services provider based in Washington, DC.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 8 | 12 contacts → | ||||
Partial evidence “Tenenbaum Law Group PLLC is a nationally recognized, eight-attorney boutique Washington, DC-based law firm specializing in the representation of nonprofit organizations.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 9 | 12 contacts → | ||||
Partial evidence “WATKINSON MILLER PLLC is a law practice company based out of 1100 New Jersey Ave SE Suite 910, WASHINGTON, District of Columbia, United States.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 10 | 11 contacts → | ||||
Partial evidence “Klamp & Associates is a law firm dedicated exclusively to representing charitable organizations.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 11 | 9 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 12 | 9 contacts → | ||||
Indirect evidence “For more than forty years, we at Harmon, Curran, Spielberg + Eisenberg, LLP, have served the legal needs of individuals and organizations to help them advance social, economic and…” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 13 | 9 contacts → | ||||
Indirect evidence “Integer is a full-service advocacy firm in Washington, D.C, specializing in economic and nonprofit policy.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 14 | 7 contacts → | ||||
Indirect evidence “Nationally-recognized and award-winning economists, lawyers and public policy experts providing public policy analysis; business process improvement; research and analysis…” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 15 | 5 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 16 | 5 contacts → | ||||
Partial evidence “McIntyre & Lemon, PLLC helps clients efficiently navigate the complex maze of federal and state laws and regulations.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 17 | 3 contacts → | ||||
Indirect evidence “DC Refers was created to increase access to justice for persons of modest means in the District of Columbia.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 18 | 3 contacts → | ||||
Partial evidence “Garner Law PLLC is a small law firm with its focus on providing passionate, dedicated representation to clients in Maryland and the District of Columbia.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 19 | 2 contacts → | ||||
Partial evidence “Founded in 2020, the Law Office of Attorney Ambur C.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 20 | 2 contacts → | ||||
Indirect evidence “Compass Legal Group offers experienced legal guidance to public officials, candidates, and nonprofit organizations on campaign finance, government ethics, and nonprofit tax and…” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 21 | 1 contacts → | ||||
Indirect evidence “Red Cliff Legal can help with entity formation, corporate governance, contract drafting & review, employment matters, policy creation, and intellectual property issues.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 22 | 1 contacts → | ||||
Indirect evidence “Outside General Counsel to Small Businesses and Non-Profit Organizations in the District of Columbia - Specializing in Business Formation, Incorporation, Business Licensing…” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 23 | 1 contacts → | ||||
Partial evidence “Whether you are a new business just getting started or a multi-national company seeking assistance with reporting and restructure compliance, our team at 10K Law can solve even…” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 24 | 1 contacts → | ||||
Indirect evidence “Trusted legal counsel delivering critical legal and business strategies and representation to clients in the public and private sectors in addition to the nonprofit and…” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 25 | 1 contacts → | ||||
Partial evidence “Lockard Law, PLLC is a company based out of Washington, DC, United States.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
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: 501c3 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 501c3 law firms.
- Partial evidence
- Its own public description names part of 501c3 law firms, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name 501c3 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 45 501c3 law firms based in Washington, United States
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501c3 law firms based in Washington, United States at a glance
As of Sep 27, 2026Companies by employee count
Freshness & accuracy
How recently the business emails were verified and the company information checked
Email last verified
Median 30.0dCompany record updated
Median 66.0dHow 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 501c3 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 “501c3 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 501c3 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 501c3 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, 268 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 27, 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.
501c3 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 501c3 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 501c3 law firms are there based in Washington, United States?
RevenueBase identified 45 501c3 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?
Reno & Cavanaugh, Pllc, headquartered in Washington, tops this list with the largest team on record.
Which city in the United States has the most 501c3 law firms?
New York leads the United States with 36 headquartered companies, followed by Washington (32) and Chicago (22).
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 268 verified decision-maker contacts tracked across these 45 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 27, 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.