Mr. Duncan’s practice includes work relating to the acquisition and valuation of real property for governmental entities, private landowners, eminent domain law, private condemnation, inverse condemnation, highway access matters and selective civil litigation. Current and past clients include a variety of private landowners, the E-470 Public Highway Authority, the Colorado Department of Transportation, the Regional Transportation District, the cities and Towns of Aurora, Arvada and Longmont, Arapahoe County, the Cherry Creek School District, and a variety of special districts. He has been hired by RTD to help represent it on the FasTracks Project.

Mr. Duncan spent his first years in practice with the United States Department of Justice (1974-1979) and the State of Colorado Attorney General’s office (1979-1984). He has been in private practice since 1985 and a member of the law firm of Duncan, Ostrander & Dingess, P.C. since it was founded in 1990. He has obtained an AV rating from Martindale-Hubbell. Mr. Duncan was selected as a 2010 Colorado Super Lawyer and he was recently selected by his peers as one of The Best Lawyers in America® in the specialty of eminent domain and condemnation law.

In 1987, Mr. Duncan received a gubernatorial appointment to Colorado's Commission on Judicial Discipline. In 1990, Governor Romer appointed him to the State Board for Community Colleges and Occupational Education; the Governor re-appointed him in 1994. In 2007 Governor Ritter appointed him to the State Commission on Judicial Performance for the Second Judicial District.

His educational background includes a B.A. from Johns Hopkins University in 1971 and a J.D. from the University of Denver College of Law in 1974 where he was an editor of The Denver Law Journal. He also served a judicial clerkship.

Mr. Duncan is President of the Colorado Chapter of the Johns Hopkins University Alumni Association. He is involved in a variety of community activities. He is a frequent speaker at Continuing Legal Education Seminars on eminent domain matters. He is a member of the Legal Aid Foundation and he coaches lacrosse at Regis Jesuit High School.