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We Help You Grow a Better Tomorrow


If you're looking for a full service cannabis law firm in Colorado, look no further than Thorburn Law Group. We have a team of experienced attorneys who can help you with all aspects of the cannabis industry, from licensing and compliance to tax and estate planning. We also have a wide network of industry contacts that we can put you in touch with, so you can get the support you need to succeed in this rapidly growing industry. Contact us today to learn more about how we can help you grow your business.


We offer a full suite of legal services to entities of all types and sizes that work within or alongside the regulated cannabis and hemp industry. If you are considering hiring an attorney for your cannabis and/or hemp business needs, we suggest reading through our practice areas listed here that will answer common questions you may have about the process. 


If you are in the cannabis industry, it is important to have a tax law firm that understands the IRS's and Colorado's stance on cannabis businesses. The IRS and Colorado have taken a hands-on approach to cannabis businesses. A good tax law firm can help you navigate the tax code and make sure that you are compliant with all of the regulations.

We provide representation throughout the audit process, from inception to completion. We represent clients in federal and state audits, including but not limited to: 280E, income, sales and use, occupational privilege, and personal property tax.


Colorado has become a hotspot for cannabis litigation. The state's legalization of recreational cannabis has led to a boom in the industry, and there are now many cannabis businesses operating in the state. However, this new industry is not without its challenges. There have been many lawsuits filed against cannabis businesses, often over issues like product liability or advertising regulations. As a result, there is a growing need for law firms that specialize in cannabis litigation. 

We provide litigation representation in all areas cannabis, including but not limited to: tax defense, land use and zoning disputes, construction disputes, contract disputes, licensing issues, and regulatory disputes. 


Colorado has some of the most progressive cannabis zoning laws in the country. The state has a variety of different types of zoning laws that allow for different types of businesses to operate in different areas. For example, there are laws that prohibit cannabis dispensaries from being located near schools and other public places. There are also laws that restrict the size and location of cannabis cultivation facilities.


If you're hoping to open a dispensary or grow operation in the state, you'll need to work with a law firm that specializes in cannabis zoning. A lawyer will be able to help you navigate the complicated process of securing the proper entitlements and permits. 

Our representation includes but is not limited to: the special use permit or other entitlements process, ensuring compliance with local zoning ordinances, and  working with local regulators and planners to ensure that the business overcomes any land use or zoning obstacles that may arise.  


Our law firm can help you with all aspects of cannabis construction, from site selection and permitting to construction and compliance. We can also help you navigate the ever-changing landscape of cannabis construction laws in Colorado. 

We represent clients from the beginning phases of construction up through the conclusion of a project.


Our law firm helps clients with legal issues related to the buying, selling, and leasing of property in Colorado. The state has very specific laws regarding cannabis-related businesses, so it's important to have a lawyer who is familiar with these laws. Our firm can help you navigate the process of getting a license to operate a cannabis business, as well as help with zoning issues and other legal matters.

We provide both transactional and litigation real estate representation, including contract and regulatory issues. 

Featured In


We are the leader in the most innovative and sophisticated cannabis litigation in the nation, and we have had several published opinions. We have received national recognition as leading litigators for the cannabis industry's highest profile cases -  and have recognized significant wins for the industry along the way.

We have caught the attention of the Supreme Court of the United States. Most notably, Justice Clarence Thomas issued a statement in our firm's Standing Akimbo v. United States case. The statement can be seen as a warning to the federal government to lay off of state legal cannabis. You can view this case along with our other published cannabis cases HERE. 

Feinberg v. Commissioner, 808 F.3d 813 (10th Cir. 2015) (Feinberg I) and Feinberg v. Commissioner, 916 F.3d 1330 (10th Cir. 2019) (Feinberg II)

Click to hear oral argument


(Published) - Argued on a writ of mandamus, in front of now Justice Neil Gorsuch. Justice Gorsuch’s opinion in Feinberg has been described as a “technical loss but an artful win for the cannabis industry.”

(Published) - Addressing the question of whether state expressly legal marijuana laws are preempted by the federal Controlled Substances Act, as well as whether 26 U.S.C. §280E violates the Sixteenth Amendment to the Constitution by taxing more than constitutional income.

(Published) - The Tenth Circuit Court of Appeals determined that costs of goods sold is a constitutionally mandated exclusion from business income for which Congress cannot interfere. 

(Published) - Arguing whether the IRS has the authority to administratively determine that a taxpayer has trafficked in a controlled substance, without a previous conviction.

(Published) - Addressing the question of whether state expressly legal marijuana laws are preempted by the federal Controlled Substances Act, as well as whether 26 U.S.C. §280E violates the Sixteenth Amendment to the Constitution by taxing more than constitutional income.

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Jonathan Smith, Lawyer

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