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Tammera R. Diehm

Both as a lawyer and a leader, flexibility and creativity are key.

My Approach

In my dual role of Firm President and practicing attorney, there are more similarities than differences. In both cases, whether representing the firm or our clients, my ultimate goal is to find the right path forward, making it easier and more efficient to do business.  At times, this means I am discussing strategic business opportunities, while other times I am working through a thorny technical issue. More often than not, I am serving in an advisory role and finding the best person for the job at hand, whether that is me or another member of our team.

Firm President

I see my role of Firm President as that of a coach, motivating team members and helping each individual unlock his or her potential. Each person approaches their practice differently, and that approach evolves and changes over time. As I work to oversee all aspects of firm management and operations, I want to give each of our firm members the ability to build their own career, offering flexibility and support while maintaining our firm’s core values and commitment to client service. My “onboarding” as President included navigating issues no one could have predicted – a global pandemic, widespread economic uncertainty, and nationwide civil unrest – but I feel fortunate to have had such a rich training opportunity. Through it all, each individual stepped up to the challenge, responded with creativity and teamwork, and didn’t miss a beat in their ardent representation of our clients.

Legal Practice

In addition to guiding the firm as the coach, I am not afraid to roll up my sleeves and get to work alongside my teammates. My legal work includes all aspects of real estate transactions, including buying, selling, leasing, developing and financing. My day-to-day world focuses heavily on mergers and acquisitions – if it involves real property, it involves me. I have a particular interest in multi-unit real estate, especially in the downstream energy, convenience store, and franchise quick-serve restaurant industries. In my practice, the law serves as a tool to help navigate all the complicated aspects of doing business when you own or occupy real estate – complicated zoning, land use, government approvals or regulatory compliance – I sift through these issues and find practical solutions for my clients.

My work also includes governance and compliance. Whether I am representing a charitable organization or a trade association, I provide guidance on how to comply with corporate, tax and campaign finance regulations.

Practice Areas

Honors & Awards

Notable Women in Commercial Real Estate

Twin Cities Business, 2022

100 People to Know – Overachiever Category

Twin Cities Business, 2021

Excellence in Leadership

MNCREW, 2021

Minnesota Super Lawyers®

Top 50 Women, 2018, 2020

Notable Women in Law

Twin Cites Business Magazine, 2020

Recommended in Real Estate

Chambers USA: America’s Leading Lawyers For Business, 2020-2023

Recommended in Real Estate: Zoning/Land Use

Chambers USA: America’s Leading Lawyers For Business, 2022-2023

Leaders in their Field

Real Estate
Chambers USA

MSBA North Star Lawyer

Pro Bono Service, 2012-2022
All-Star Lawyer 2020

Top Women in Finance

Finance & Commerce, 2014

The Best Lawyers in America©

Minneapolis Lawyer of the Year: Eminent Domain and Condemnation Law, 2022
Minneapolis Lawyer of the Year: Municipal Law, 2017, 2019
Municipal Law, 2010-2024
Land Use and Zoning Law, 2013-2024
Real Estate Law, 2018-2024
Eminent Domain and Condemnation Law, 2020-2024

40 Under Forty Honoree

Minneapolis/St. Paul Business Journal, 2010

Rising Stars

Minnesota Super Lawyers®, 2007-2012

Up & Coming Attorney

Minnesota Lawyer, 2006

Associations & Memberships

American Bar Association


Minnesota State Bar Association

Public Law Section
Real Property Section

Anoka County Bar Association

Minnesota Commercial Real Estate Women



(Commercial Real Estate Development Association)
Minnesota Chapter; Chair, Community Enhancement Committee, 2017-present

Minnesota Petroleum Marketers Association

National Association of Convenience Stores

Minnesota Service Station & Convenience Store Association

Society of Independent Gasoline Marketers of America


Member, Board of Directors, 2016-present
Chair, Board of Directors, 2019-present


Board Member Emeritus, 2020-present
President, Board of Directors, 2013-2015
Member, Board of Directors, 2011-2020
Volunteer, 2004-present

City of Columbia Heights

City Council, 2003-2014
City Council President, 2007-2014
Appointed Commissioner, Planning and Zoning Commission, 2000-2002
Charter Commission, 1998-2002
Charter Commission President, 2000-2002
Appointed Commissioner, Economic Development Authority, 2003-2014
Housing and Redevelopment Authority, 2003-2016
Housing and Redevelopment Authority Chair, 2006-2016

Metropolitan Council Land Use Advisory Committee

Member, 2007-2014
Vice Chair, 2011-2014

Nicollet-Central Policy Advisory Committee

Member, 2012-2013

Hennepin County Bar Association

Chair, Eminent Domain Section Committee, 2017-2018
Vice Chair, Eminent Domain Section Committee, 2016-2017

Winthrop & Weinstine, P.A.

Board of Directors, 2018-present

Columbia Heights Alumni Scholarship Foundation

Board Member 2019-present

American College of Real Estate Lawyers

Elected 2021

Fellows of the American Bar Foundation

Elected 2021

Children’s Theatre Company

Board of Directors, July 2023-present

Detroit Regional Chamber

Minnesota Women’s Economic Roundtable

Member, 2023-