Who We Are

Abigail Rivenbark Brown

Founding Attorney

Abigail Brown PhotoAttorney. Abby is a water rights attorney who regularly appears before the Montana Water Court and state district courts in adjudication and administration proceedings. She also assists clients with transactional and regulatory matters involving water rights.

Conflict Resolution Professional. Abby is  a certified mediator with the Montana Mediation Association, offering mediation and conflict coaching services to water users, environmental and water user groups, and Tribal governments as an alternative to litigation or in connection with potential settlement discussions in existing litigation. Abby is a certified conflict resolution facilitator as well, partnering with other organizations to facilitate community dialogues and stakeholder meetings.

Abby offers mediation, facilitation, and conflict coaching services for non-water right related disputes, including (but not limited to) creating or amending parenting plans, facilitating community or neighborhood disputes, and addressing business, organizational, or local government conflicts.

Background. After growing up in the southeastern United States, Abby earned a B.S.Ed. from Northwestern University in Evanston, Illinois. She then served in the United States Peace Corps, living and working for two years in a rural village in Malawi, East Africa. It was in Malawi that Abby developed a deep appreciation for, and interest in, the fundamental and complex relationship between water use and a community’s health and food security.

Eventually, Abby made her way to Montana where she obtained a Master’s of Art in youth and family development, focused on cross-cultural conflict resolution from the University of Montana in Missoula, Montana. Abby went on to earn a J.D. with honors from the University of Montana School of Law. Prior to entering private practice, Abby clerked for Retired Justice Patricia O. Cotter at the Montana Supreme Court.

In addition to her private water law and mediation practice, Abby believes strongly in giving back to the community through pro bono legal work. Abby currently partners with Trust Montana to provide independent legal consultations to buyers purchasing homes in as part of a Community Land Trust project. Abby is a member of the State Bar of Montana’s Water Law Section and Standing Committee on Self-Represented Litigants for the Montana Supreme Court’s Access to Justice Commission, having completed terms as executive officers for both organizations.

Ever the student, Abby will earn her L.L.M. in Water and Environmental Law from McGeorge Law School in December 2021.

​Outside of her legal career, Abby, her husband Collin, and their two young sons, enjoy the great outdoor life Montana offers. She is also a yoga instructor who volunteers her time teaching yoga(ish) movement and mindfulness in local preschool and elementary school programs.


Ann Olson

Legal Assistant

Ann OlsonAnn was born and raised in Montana. She graduated with honors from the Legal Administrative Support program at Helena College.

Ann has experience in water law and estate planning. At ARB Law Group, Ann provides legal assistance to the attorneys on an array of matters, from transaction to litigation.

In her free time, Ann enjoys reading and adventuring with her young daughter.