Williamson and Hayashi, LLC, is  committed to providing you with professional, experienced, and  personalized legal service for your municipal law needs.  Dave and Bill are graduates of the University of Colorado School of Law.   Our team understands the multiple facets involved in municipal law  matters and uses each of our relative experiences and areas of expertise  to efficiently and effectively meet your needs.  


David ("Dave") S. Williamson, Attorney

Dave earned his J.D. from the University of Colorado School of Law in 1977.  Dave also has a bachelor of science from the University of Colorado Business College in Finance (Cum Laude), which he received in 1974.

Dave has been involved in municipal law practice since 1986, with experience as a deputy county attorney for Loudoun County, Va.; deputy city attorney for Thornton, Co.; and as an associate attorney at Windholz & Associates.  He was part of the Windholz & Associates team from February 1990 through February 2008, at which time Williamson and Hayashi, LLC, was formed.  Dave is presently the City Attorney for the Cities of Golden and Lafayette.  Other current and recent clients include:  City of Sheridan; City of Federal Heights; City of Edgewater; Estes Park Urban Renewal Authority; City of Longmont (Board of Adjustment); City of Walsenburg (Annexation, Land Use and Special District Matters); City of Westminster (Special Permit and License Board, and Sales and Use Tax Matters); and City of Thornton (Local Licensing Authority and Sales Tax matters).

Dave has been, and is active in several professional organizations, including:  the Colorado and Virginia Bar Associations; the Boulder County, Colorado, and Loudoun County, Virginia, Bar Associations; Metropolitan Denver City Attorney's Association; Colorado Municipal League, Attorneys Section; and Virginia Local Government Attorney's Association.

William ("Bill") P. Hayashi, Attorney

Bill earned his J.D. from the University of Colorado School of Law in 1987, after receiving a Masters in Public Administration (1981) from the University of Colorado and a Bachelor of Arts, History from Denison University in Granville, Ohio. (1977).

Bill began his law career in the municipal law practice area, first as a law clerk for the City of Broomfield, then as an associate attorney at Windholz & Associates from December 1987 and February 2008, when Bill joined Dave Williamson in forming Williamson and Hayashi, LLC.  Bill is presently the city attorney for the Cities of Federal Heights and Sheridan.  Other current and past clients include:  Assistant City Attorney for the Cities of Golden and Lafayette; Edgewater; Special Counsel for Estes Park Urban Renewal Authority; Municipal Prosecutor for the Cities of Broomfield, Edgewater, and Golden; Special Counsel to Commerce City (Personnel); Federal Heights (Codification); Westminster (Prosecutor); Broomfield (Liquor Prosecution); Federal Heights (Prosecutor); and Longmont (Board of Adjustment).

Bill is a member of the Metro City Attorney's Association; and Colorado Municipal League, Attorneys Section.

Keith Martin 

Keith earned his J.D. from DePaul University in 2009, after receiving a Bachelor of Science in Forestry from Colorado State University in 2004.  Prior to joining Williamson and Hayashi, LLC, Keith worked as an associate attorney at Hoffmann, Parker, Wilson & Carberry, P.C., where he served as a municipal prosecutor to several home rule and statutory towns and cities, represented clients in eminent domain and sales and use tax litigation, and advised clients on various legal issues related to tort liability, governmental immunity, open meetings, open records, employment, land use, legislative amendments, law enforcement, tax, and nuisance abatement.   He began his legal career in 2009 working as a law clerk for the City of Chicago in the Drug and Gang House Enforcement Section, eventually becoming an Assistant Corporation Counsel for the City of Chicago in 2011.  As an Assistant Corporation Counsel, he handled various civil litigation matters before administrative, state and federal courts, including public nuisance enforcement actions, employee disciplinary suspension appeal hearings, police discharge proceedings, and complex federal civil rights cases brought under 42 U.S.C. §1983.  Keith is an avid mountain biker who loves spending time outdoors with his family, teaching them about all Colorado has to offer and the importance of environmental sustainability.  

Julie Robbins, Legal Assistant

Julie received her B.A., in anthropology, from the University of Colorado, Boulder, in May, 2004. She went on to the School of Education at the University of Colorado, Boulder, and in January 2006 was granted a license as a social studies teacher at the secondary level.  Julie has worked in the legal profession for over 35 years, beginning in California where she worked for firms in both Los Angeles and Del Mar, California, and has a broad based experience of working in family law, estate, probate, general civil litigation, and bankruptcy, as well as the bank and finance areas of law.  Julie decided to return to working as a legal assistant instead of teaching and began working as a legal administrator with Windholz & Associates in January 2007.  Julie became the office manager for Williamson & Hayashi, LLC, in March of 2008.  Julie is pleased that she now adds a new area of practice to her resume, municipal law, in working with Dave and Bill , and the cities they represent.

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