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Firm Background:

The Peithmann Law Office was founded in Farmer City in 1948 by Ortheldo A. Peithmann and his CPA wife, Winona C. Peithmann, as a general practice law firm with a tilt toward municipal law, farm estate planning and tax matters. Bill Peithmann joined the firm in 1985 after a stint as international corporate counsel in California. In May, 2012, the firm re-located 15 miles east to Mahomet, Illinois, where Bill and his wife Lisa have lived since 2006.

Durable, Capable, Reliable:

Over time the firm has narrowed its practice to providing customized tax, estate planning, wealth management and related services to select clients throughout Illinois and Colorado. The Peithmann Law Office is dedicated to providing only the highest quality legal services, equivalent or superior to that provided by larger firms in more urban venues, and proudly stands behind its work. As a result The Peithmann Law Office is regularly cited by its peers as among the very best in Illinois.

Since 2011 the firm has been included in the "U.S. News and World Report America’s Best Law Firms"® with a Tier 1 metropolitan ranking for Trusts and Estates law.

Limited Practice:

The Peithmann Law Office limits its practice to select matters involving wealth management and preservation; asset protection; basic, intermediate and advanced estate planning; trust and estate administration; fiduciary support; charitable organizations; contested estates; elder law; closely-held businesses (especially, family farm operations); business succession planning; commercial and farm real estate; and gift, estate and income taxation of all types. This limited practice may include any one or combination of the following planning, support or legal services:

* Closely and privately held businesses – especially, family farm operations

* Creative ownership methods and organizations

* Customized estate and business succession planning, including appropriate asset protection and tax avoidance techniques, valuation discount strategies, and tailored multi-generation transfer and administrative provisions

* Wills, and trusts of almost every kind

* Powers of appointment

* Special needs, "elder law", guardianships and medicaid planning

* Probate and post-mortem estate planning

* Disclaimers

* Trust and estate administration

* Contested estates

* Fiduciary accounting, tax and administrative support for non-professional family trustees

* Residential, commercial and farm real estate matters of all types

* Gift, estate, generation-skipping and income tax planning, compliance and audits

* Qualified expert case analysis on applicable law, methods and practice

* Retained to assist local counsel in all four Illinois downstate appellate districts

The Peithmann Law Office is very selective in the new clients and referrals it accepts.


All Illinois law firms are required to charge "reasonable fees", and The Peithmann Law Office is no exception. While certainly not a low cost provider we believe our fees are very competitive with other firms of similar experience and abilities providing similar legal services, and are substantially less than the fees charged by equivalent firms in Chicago or its collar counties.

All fees are established by prior agreement on terms intended to be commensurate with the value of the work performed and the results attained for the benefit of the client.

Farms and Farming:

Bill Peithmann is a member of the DeWitt County and Piatt County Farm Bureaus and a Commissioner of the Clintonia Union drainage district. He actively manages several small Central Illinois farm operations and also acts as trustee or trustee's agent on behalf of several charitable and non-charitable beneficiaries.

More than half of the firm's clients are engaged, directly or indirectly, in farming.

Speaking and Writing:

Bill Peithmann is also a frequent contributor to legal publications on estate planning matters and lecturer at various tax and estate planning institutes for the American Bar Association, the Illinois Institute for Continuing Legal Education, the Illinois State Bar Association, the Colorado Bar Association, the University of Illinois College of Law, and other professional organizations, on such topics as basic and advanced estate planning and administration, qualified disclaimers, applied valuation discount theory, powers of appointment, advising and protecting fiduciaries, the practical use of revocable and irrevocable trusts, and the various features of the generation skipping transfer tax scheme. He has also provided expert testimony before the civil judiciary panels of the Illinois Senate and the Illinois General Assembly.

Contact & Links


  • 409 East Main Street
    P.O. Box 80
    Mahomet, IL 61853

Bar Admissions

  • Colorado, Colorado Bar Association
  • Illinois, Illinois State Bar Association
  • California, The State Bar of California


  • American Bar Association - Real Property, Probate & Trust Law Section (B-1 Generation Skipping Transfers Committee, Vice-Chair 1994 - 1998)
  • American College of Trust and Estate Counsel (ACTEC) - Fellow (elected 1994)
  • Illinois Bar Foundation - Pillar of the Profession Fellow (Bd. of Directors, 1997-98; 2000-03; 2015-; Treasurer, 2016 -17; 3rd Vice President, 2017 - 2018; 2nd Vice President, 2018 - 2019; 1st Vice President, 2019 - ) -
  • Illinois State Bar Association - Board of Governors, 1995 - 2001
  • Mahomet Area Youth Club (MAYC) - Director; Vice President (2013 - 2016)

Court Admissions

  • United States Supreme Court

Lawyer of the Year Badge - 2016 - Trusts and Estates Lawyer of the Year Badge - 2013 - Trusts and Estates

Named "Lawyer of the Year" by Best Lawyers® for:

  • Trusts and Estates, Springfield, IL (2016)
  • Trusts and Estates, Springfield, IL (2013)

Recognized in The Best Lawyers in America® 2023 for work in:

  • Tax Law
  • Trusts and Estates

Special Focus

  • Agribusiness
  • Asset Protection
  • Business and Succession Planning
  • Estate Planning
  • Fiduciary Tax
  • Finance
  • Nonprofit Organizations and Charitable Giving
  • Tax
  • Trusts and Estates
  • Wealth Management


  • Past Chair, Illinois State Bar Association's Trusts & Estates Section
  • Rated by Illinois "Super Lawyers" in the fields of "Estate Planning & Probate" law, "Tax" law, and "Estate & Trust Litigation" law since 2006
  • Who's Who in American Law
  • Best Lawyers in America® (“Trusts & Estates” and “Tax” matters) since 1999
  • Illinois State Bar Association Board of Governors Award 1998
  • Leading Illinois Attorney (now, “Leading Lawyers”) since 1996 in the areas of “Agriculture Law”, “Real Estate Law: Commercial”, “Real Estate Law: Residential”, “Tax Law” and “Trust Will & Estate Planning Law”. www. leading lawyers.com
  • AVVO Rating 10 of 10; "Superb" since 2015
  • Martindale-Hubbell “AV” rating in 1994
  • Cited by Leading Lawyers Magazine – Business Edition as one of the "Top Ten Downstate" lawyers in Illinois in 2018 & 2019.
  • Cited by Leading Lawyers Magazine -- Real Estate Edition as one of the "Top Ten Downstate Real Estate Related" lawyers in Illinois in 2015 and 2017, 2018 and 2019.
  • U.S. News and World Report America’s Best Law Firms® with a Tier 1 metropolitan ranking for Trusts and Estates law, 2011 - 2019
  • Cited by Leading Lawyers Magazine – Consumer Edition as one of the "Top Ten Trust, Will & Estate Planning" lawyers in Illinois in 2013, 2014, 2015. 2016, 2017, 2018 and 2019.
  • Cited by Leading Lawyers Magazine – Real Estate Edition as one of the "Top Ten Agriculture” lawyers in Illinois in 2013, 2014, 2015 , 2016, 2017, 2018, and 2019.

Iran - United States Claims Tribunal (1981 - 1983)

Attorney, International Exploration and Production Division, Getty Oil Company (Los Angeles; 1980 - 1983).
As a very young lawyer with an interest in international law I had the rare opportunity to represent Getty Oil (in consortium with other major and mid-major oil companies) in landmark international arbitration proceedings following the 1981 "Algiers Accords" that resolved the Iran hostage crisis and other issues between the United States and the Islamic Republic of Iran.

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