Riordan and Horgan, founded in 2003, is a "lawyer's law firm," specializing in motions, writs, and appeals in complex criminal and civil litigation. Led by Dennis P. Riordan, widely recognized as one of the country's leading appellate advocates, the partnership between Mr. Riordan and Donald Horgan represents clients in a sweeping range of criminal and civil matters. The firm regularly appears in trial courts, generally in association with other counsel, to brief and argue complex motions before during, and after trial. Mr. Riordan and Mr. Horgan have also successfully served as lead trial counsel in both state and federal criminal prosecutions.

Best known for an impressive record of success in criminal matters, the firm also has prevailed in numerous civil appeals, winning decisions in the Ninth Circuit, California Supreme Court, and California Courts of Appeal in cases as varied as bad faith insurance judgments, class action wage and hour claims, and medical doctor disciplinary matters. While appearing most frequently in California federal and state courts, the firm has argued cases in federal circuits around the country and the United States Supreme Court.    

Riordan and Horgan, founded in 2003, is a "lawyer's law firm," specializing in motions, writs, and appeals in complex criminal and civil litigation. Led by Dennis P. Riordan, widely recognized as one of the country's leading appellate advocates, the partnership between Mr. Riordan and Donald Horgan represents clients in a sweeping range of criminal and civil matters. The firm regularly appears in trial courts, generally in association with other counsel, to brief and argue complex motions before during, and after trial. Mr. Riordan and Mr. Horgan have also successfully served as lead trial counsel in both state and federal criminal prosecutions.

Best known for an impressive record of success in criminal matters, the firm also has prevailed in numerous civil appeals, winning decisions in the Ninth Circuit, California Supreme Court, and California Courts of Appeal in cases as varied as bad faith insurance judgments, class action wage and hour claims, and medical doctor disciplinary matters. While appearing most frequently in California federal and state courts, the firm has argued cases in federal circuits around the country and the United States Supreme Court.