Tatum O'Brien | O'Keeffe O'Brien Lyson Foss Attorneys

Tatum O’Brien



When you think of a quality that describes the attorney working for you, does “tenacious” come to mind? That’s what Tatum’s clients say about her.

Tatum was born and raised in Western North Dakota. Her extensive experience in and out of the courtroom, coupled with a work ethic that simply doesn’t stop, has earned her a solid reputation as an attorney who represents her clients with tenacity and skill.

Tatum’s areas of concentration include criminal law, personal injury, and general litigation. Prior to joining the firm, she was a law clerk for all eight judges in the East Central Judicial District, Cass County, North Dakota.

Tatum earned her undergraduate degree in Sociology with criminal justice emphasis from North Dakota State University, Fargo, North Dakota. She graduated with distinction from the University Of North Dakota School Of Law. While in law school, Tatum was a law clerk at the Morley Law Firm, Grand Forks, North Dakota. Tatum also spent a summer as an extern with the US Attorney’s Office, District of North Dakota.

Community Involvement

  • Firstlink, Board Member and Chair of Governance Committee


    • Dalwhinnie Award for Exemplary Trial Work by North Dakota Association for Criminal Defense Lawyers in 2010
    • Top 100 Trial Lawyers, National Trial Lawyers
    • SuperLawyer

Admitted to Practice in
  • North Dakota
  • Minnesota
  • South Dakota
  • Federal Courts in North Dakota
  • Federal Courts in South Dakota
  • Federal Courts in Minnesota
  • 8th Circuit Court of Appeals
Professional Memberships
  • Minnesota State Bar Association
  • State Bar Association of North Dakota
  • Cass County Bar Association
  • North Dakota Association for Justice, Executive Board, President-Elect
  • Clay County Bar Association
  • UND Law Mentor Program
  • South Dakota Bar Association
  • Criminal Justice Act Panel for Federal  Appointments
  • Ronald Davies Inn of Court
  • Past President – North Dakota Association for Criminal Defense Lawyers
  • American Association for Justice – Revitalization Governor, Board of Governors
  • Injury Board