Duffy Dillon

Duffy Dillon is the founder of Dillon | Grube and is one of the most experienced trial lawyers and business advisors working in Rock County today. Duffy spent nearly two decades handling personal injury claims for both accident victims and insurance companies. After founding Dillon | Grube in 2019, he now focuses his practice on helping clients in four areas — personal injury, civil litigation, outside general counsel, and family law.

Born and raised in Janesville, Duffy returned in 2000 and has served numerous nonprofit organizations since, including: United Way, Humane Society of Southern Wisconsin, Janesville Performing Arts Center, Janesville Youth Baseball & Softball Association, Janesville Basketball Association, and the Janesville Generations Fund, a component fund of the Community Foundation of Southern Wisconsin.

 
 

Joshua Patrick Grube

Joshua Grube is an aggressive trial lawyer and one of the most experienced criminal defense lawyers working in Rock County today. As a 16-year veteran State Prosecutor and private bar defense attorney, Joshua has tried over 100 cases to a judge or jury. From disorderly conduct and drunk driving cases to felony drug delivery and child sexual assault charges, Joshua has routinely convinced juries to side with him. He focuses his practice on criminal defense and labor law issues.

Joshua, who is fluent in Spanish, has also spent much of the past two decades forging relationships and working with philanthropic organizations in Rock and Walworth counties, and beyond. He has served on multiple local boards and been awarded for his efforts in advocating for victims of sexual assault and violence.

 
 

Jonathan W. Groessl

Jonathan W. Groessl joined Dillon | Grube in January 2021 after working for over 30 years at well-known local law firms. Before locating to Janesville, Jon worked in the Business Combinations areas for an international accounting firm, in the mergers and acquisitions area of a private equity firm, and as the Assistant General Counsel for a major heavy equipment and truck trailer manufacturing concern for several years.

A Wisconsin native, Jon concentrates in the areas of corporate, real estate, construction and business law. 

 
 

Katharine Cullen

Katharine Cullen is an associate litigation attorney with Dillon | Grube. Katharine focuses her practice on criminal and traffic defense matters, personal injury, and civil litigation.  She understands her clients’ goals and believes clear communication is the key to achieving successful outcomes.

Katharine is a Janesville native. Along the way, while earning her law degree, she worked to free the wrongly convicted with the Wisconsin Innocence Project.

 
 

Wisconsin Areas Served

Dillon | Grube’s offices are located in Janesville, but our practice area extends throughout southern Wisconsin. From the Wisconsin/Illinois border north to Portage and as far east as Milwaukee to west of Madison, when you need lawyers you can trust, turn to Dillon | Grube.

  • Janesville
  • Milton
  • Beloit
  • Fort Atkinson
  • Edgerton
  • Jefferson
  • Delavan
  • Walworth
  • Sun Prairie
  • Lake Geneva
  • Whitewater
  • Stoughton
  • East Troy
  • Palmyra
  • Eagle
  • Elkhorn
  • Fitchburg
  • Madison
  • Milwaukee
  • Fontana
  • Cottage Grove
  • Lake Mills
  • Johnson Creek
  • Cambridge
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