Atty. John T Callahan

Atty. John T Callahan

John T Callahan is a lawyer practicing intellectual property law, patent infringement, litigation. John received a B.Ch.E. degree from Catholic University in 1985, and has been licensed for 36 years.

Washington Washington 36 yrs experience 36 year
Call (771) 218-3541 Book Appointment

Profile Summary

About John T Callahan at a glance

John T Callahan is a Member based in Washington, District of Columbia, practicing at Sughrue Mion, PLLC. They have 36+ years of legal experience, licensed to practice since 1990. Their practice focuses on patent, real estate, ip, and litigation. Admitted to practice in District of Columbia registered to practice before the U.S. Patent and Trademark Office (1990). Educated at University of Baltimore (J.D., 1990) and Catholic University (B.Ch.E., 1985). Active member of District of Columbia Bar. Serands clients in Washington, DC and the surrounding metropolitan area.

Verified attorney profile · Updated June 2026

About

  • John T Callahan is a lawyer practicing intellectual property law, patent infringement, litigation
  • John received a B.Ch.E. degree from Catholic University in 1985, and has been licensed for 36 years
  • John practices at Sughrue Mion, PLLC in Washington, DC

Practice Areas Explained

John T Callahan's Areas of Practice

Each practice area below reflects the types of cases John T Callahan handles, with a brief overview of what that area of law covers.

Patent Law

John T Callahan is one of 20,749 patent attorneys indexed nationally. Browse patent attorneys in District of Columbia →

Real Estate Law

Real estate attorneys handle home purchases, sales, commercial transactions, title disputes, and landlord-tenant matters.

John T Callahan is one of 316,149 real estate attorneys indexed nationally. Browse real estate attorneys in District of Columbia →

Intellectual Property

IP attorneys protect inventions, brands, and creative work through patent prosecution, trademark registration, copyright, and trade-secret enforcement.

John T Callahan is one of 106,079 ip attorneys indexed nationally. Browse ip attorneys in District of Columbia →

Civil Litigation

Civil litigation attorneys for breach of contract, business disputes, civil rights, and class action lawsuits.

John T Callahan is one of 454,532 litigation attorneys indexed nationally. Browse litigation attorneys in District of Columbia →

Jurisdictional Context

Why local counsel matters in District of Columbia

Practicing law in District of Columbia. Legal matters in District of Columbia are governed by state-specific rules of civil and criminal procedure, statutes of limitations, and substantive law. Cases originating in Washington are typically filed in the local municipal court or the appropriate District of Columbia state district court, depending on subject matter and amount in controversy. An attorney licensed in District of Columbia brings working knowledge of local procedural deadlines, judicial practices in this andnue, and the substantive law that applies to cases brought here. Out-of-state attorneys generally cannot represent clients in District of Columbia courts without local counsel or pro hac vice admission.

Looking for additional District of Columbia attorneys? Browse all attorneys in Washington or all attorneys in District of Columbia.

Frequently Asked

Common questions about John T Callahan

Where is John T Callahan's law office located?
John T Callahan's law practice is located in Washington, District of Columbia. The firm is Sughrue Mion, PLLC. You can contact the office directly through this profile page.
What practice areas does John T Callahan handle?
John T Callahan focuses on patent, real estate, ip, litigation. Each practice area listed reflects experience handling cases of that type in District of Columbia.
How long has John T Callahan practiced law?
John T Callahan has 36+ years of legal experience and has been licensed since 1990.
Where did John T Callahan go to law school?
John T Callahan earned their education at (J.D., 1990); (B.Ch.E., 1985).
How can I contact John T Callahan for a consultation?
You can contact John T Callahan directly through this profile page. Click "Ask the Attorney" to submit a question, or "Schedule a Consultation" to book a meeting. Most claimed-profile attorneys respond within one business day.

Education

J.D.
University of Baltimore
- 1990
B.Ch.E.
Catholic University
- 1985

Bar Admissions

District of Columbia registered to practice before the U.S. Patent and Trademark Office
Admitted: 1990

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