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Law Offices of Heather J. Mattes
Fighting For Pennsylvania Clients For Over 30 Years

Heather J. Mattes

Heather J. Mattes

Sole Practitioner
West Chester, Pennsylvania
(484) 244-5077

Heather J. Mattes is an experienced criminal lawyer. She was born in Philadelphia, Pennsylvania and has lived and practiced here throughout her career. Ms. Mattes grew up in Delaware County where she attended public school and participated in the music program graduating as a national honor society member. In 2003, she was inducted into Sun Valley's "Wall of Fame."

Ms. Mattes attended The Pennsylvania State University where she graduated Summa Cum Laude with a degree in Communications Studies emphasizing ethics and philosophy. She graduated from the Villanova University School of Law and began her early practice as an Assistant Public Defender in West Chester, Pennsylvania for three years defending indigent clients at all levels of prosecution and in the state appellate courts.

For sixteen years, Ms. Mattes was an Assistant District Attorney in Delaware County, Pennsylvania where she tried misdemeanor and felony cases from driving under the influence to capital homicide as well as sexual assault and other special victim matters. She mentored and supervised other attorneys during her tenure.

Since 2005, Ms. Mattes has limited her practice to criminal defense in the state and federal courts. She is a member of the federal Criminal Justice Panel, the Pennsylvania Bar Association as well as the National Criminal Defense Lawyers. Ms. Mattes is a member of the Board of Pennsylvania Criminal Defense Lawyers. She received commendations in 2014 and 2016 for her work with that organization.

Areas of Practice

  • 75% Criminal Defense in state courts
  • 25% Criminal Defense in Federal courts

Litigation Percentage

  • 100% of Practice Devoted to Litigation

Bar Admissions

  • Pennsylvania, 1984
  • U.S. District Court Eastern District of Pennsylvania, 1991
  • U.S. Court of Appeals 3rd Circuit, 1991


  • Villanova University School of Law, Villanova, Pennsylvania
    • J.D. summa cum laude
  • Pennsylvania State University, State College, Pennsylvania
    • Major: Communication Studies, concentration in Philosophy and Ethics

Published Works

  • "Leap of Faith" Lessons Learned in my First Year of Practice, For the Defense, 2, 2016


  • Introduction to Criminal Procedure and Forensic Evidence in the Master of Forensic Science Program of the Drexel University College of Medicine
  • Federal Forensic Evidence in the Master of Forensic Science Program at the Drexel University College of Medicine

Honors and Awards

  • Bikers Against Child Abuse, 2003
  • PACDL President and Board Commendations, 2014 - 2016

Professional Associations and Memberships

  • Drexel University College of Medicine, Adjunct Professor
  • Pennsylvania Bar Association
  • Pennsylvania Criminal Defense Lawyers Association, Board Member, 2013
  • Delaware County Bar Association
  • Chester County Bar Association, Member
  • National Association of Criminal Defense Lawyers, Member, 2012
  • American Bar Foundation, Member
  • American Bar Association, Member

Past Employment Positions

  • Chester County Public Defender's Office, Assistant Public Defender, 1985 - 1988
  • The Delaware County District Attorney's Office, Team Leader, 1994 - 2005
  • The Delaware County District Attorney's Office, Assistant District Attorney, 1989 - 2005


  • English


  • Phi Kappa Phi

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