Company lists · Data refreshed September 2026

Top 18 Constitutional law firms based in Philadelphia, United States

RevenueBase identified 37 constitutional law firms headquartered in Philadelphia, United States as of September 2026 and tracks 2,480 professional contacts across them, including 414 with verified work emails. New York is the largest hub.

This list covers constitutional law firms headquartered in Philadelphia, 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 14, 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 14, 2026 86% judged on-target in blind review
37Companies
2,480Contacts tracked
414Verified emails
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The 18 largest constitutional law firms based in Philadelphia, United States

Ranked by team size
Top 18 of 37 constitutional law firms based in Philadelphia, United States, ranked by team size, largest first. Data refreshed Sep 14, 2026. RevenueBase Smart Search rates how each company's information relates to constitutional 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.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Indirect evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 2026201-500277 contacts →

Indirect evidence

“Margolis Edelstein was founded in Philadelphia over 65 years ago.”

Source: RevenueBase Database · checked Sep 14, 2026
2Indirect evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 202651-200102 contacts →

Indirect evidence

“When our firm was founded in 1994, our idea was to build a firm of lawyers with superior academic credentials and professional capabilities who wanted to develop their practices…”

Source: RevenueBase Database · checked Sep 14, 2026
3Partial evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 202651-20050 contacts →

Partial evidence

“McEldrew Purtell is a boutique law firm based in Philadelphia specializing in catastrophic injury / wrongful death and civil rights cases nationwide.”

Source: RevenueBase Database · checked Sep 14, 2026
4Partial evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 202611-5049 contacts →

Partial evidence

“Recognized as one of the preeminent civil litigation law firms in Pennsylvania and New Jersey, the attorneys of Feldman Shepherd have established a track record of winning…”

Source: RevenueBase Database · checked Sep 14, 2026
5Indirect evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 2026n/a35 contacts →

Indirect evidence

“Founded in 2014, van der Veen, Hartshorn and Levin provides personalized legal representation to clients throughout Philadelphia and the surrounding areas.”

Source: RevenueBase Database · checked Sep 14, 2026
6Indirect evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 202611-5024 contacts →

Indirect evidence

“ABOUT THE FIRM Astor Weiss Kaplan & Mandel, LLP offers a broad range of expert legal services to its clients by providing high-quality representation.”

Source: RevenueBase Database · checked Sep 14, 2026
7Indirect evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 202651-20014 contacts →

Indirect evidence

“It takes a very special range of skills to win highly complex suits involving multiple parties and theories.”

Source: RevenueBase Database · checked Sep 14, 2026
8Indirect evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 202611-508 contacts →

Indirect evidence

“Since its founding, the firm Kohn, Swift & Graf, P.C.”

Source: RevenueBase Database · checked Sep 14, 2026
9Partial evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 202611-507 contacts →

Partial evidence

“NastLaw is a national law firm based in Philadelphia that provides clients with experienced, confident representation in the most difficult cases.”

Source: RevenueBase Database · checked Sep 14, 2026
10Indirect evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 202611-505 contacts →

Indirect evidence

“Gay Chacker & Ginsburg was founded in Philadelphia in 1965.”

Source: RevenueBase Database · checked Sep 14, 2026
11Indirect evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 20261-105 contacts →

Indirect evidence

“GLG champions for its clients’ legal needs and cultivates personal relationships with each throughout the process.”

Source: RevenueBase Database · checked Sep 14, 2026
12Indirect evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 202651-2005 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 14, 2026
13Indirect evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 20261-104 contacts →

Indirect evidence

“Charlson Braber McCabe & Denmark is the firm you've been looking for.”

Source: RevenueBase Database · checked Sep 14, 2026
14Indirect evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 202611-503 contacts →

Indirect evidence

“Founded in 1983, Bazelon Less & Feldman was born of a belief that most commercial litigation matters could best be handled by a small group of highly talented and experienced…”

Source: RevenueBase Database · checked Sep 14, 2026
15Partial evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 202611-503 contacts →

Partial evidence

“HORN WILLIAMSON, LLC is a law firm located in Center City Philadelphia that serves clients throughout the Mid-Atlantic region.”

Source: RevenueBase Database · checked Sep 14, 2026
16Partial evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 20261-103 contacts →

Partial evidence

“First Law Strategy Group is an unique law firm specializing in "Values Work." Whether you value justice, civil rights, property rights, public policy rights, or "simply" fair…”

Source: RevenueBase Database · checked Sep 14, 2026
17Partial evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 20261-102 contacts →

Partial evidence

“Founded in 1972, Lyman & Ash has a history of protecting the rights of individuals, with trial and appellate experience at all levels, and has helped shape the law through…”

Source: RevenueBase Database · checked Sep 14, 2026
18Indirect evidencePhiladelphia, PA, United StatesHQ checked Sep 14, 20261-101 contacts →

Indirect evidence

“Hope Lefeber leads a legal defense team tailored to each case she handles, including experienced investigators, top experts and professionals, such forensic experts and tax…”

Source: RevenueBase Database · checked Sep 14, 2026

Showing 18 of 37 constitutional law firms based in Philadelphia, United States

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Constitutional law firms based in Philadelphia, United States at a glance

As of Sep 14, 2026
16.7%Verified-email coverage
67.0Average contacts per company
11-50Median size (employees)
375.7%Largest-city concentration · New York
Sep 14, 2026Page data refreshed

Companies by employee count

1-10
18
11-50
12
51-200
5
201-500
1
1,001-5,000
1

Email recency for this list is measured across the whole United States list rather than for Philadelphia, so it is reported there. Company counts and contact totals on this page are exact for Philadelphia, over 37 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 constitutional 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 Philadelphia, United States whose own description of what they do matches “constitutional 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 constitutional 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 constitutional law firms, and records with no verified work email. Companies headquartered outside Philadelphia 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, 414 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 14, 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.

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 constitutional 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 constitutional law firms are there based in Philadelphia, United States?

RevenueBase identified 37 constitutional law firms headquartered in Philadelphia, 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?

Margolis Edelstein, headquartered in Philadelphia, tops this list with the largest team on record.

Which city has the most constitutional law firms?

New York leads with 139 headquartered companies, followed by Washington (75) and Chicago (66).

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 414 verified decision-maker contacts tracked across these 37 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 14, 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.