Thinking about moving? You’re not alone. Our 2024-2025 Millennial Study shows that 7.7 million millennials moved in 2024, and Colorado had the highest migration rate of this age group relative to the total moving population in the United States (34.8%). That’s a lot of fresh hiking boots hitting the trails.

But before you cruise past the Welcome to Colorful Colorado sign with a packed truck, you should know that some things that might be legal in your current state are illegal to bring into Colorado. These include common items like certain pets, fireworks, weapons, and even sealed containers of cannabis or alcohol. This article breaks down what you can’t legally bring across state lines, why it matters, and what to do instead, so you can avoid fines, delays, or worse.

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Uncertified Cats, Dogs, and Rabbits

Colorado loves animals! But if you’re moving here with pets, there are a few health requirements you’ll need to meet before crossing state lines. Most people don’t realize that it’s illegal to bring uncertified dogs, cats, or rabbits into Colorado, even if they’re family pets.

Here’s what’s required:

• For all animals. A Certificate of Veterinary Inspection (CVI), signed by a licensed vet within 30 days of arrival.
• For dogs and cats older than 3 months. Proof of a current rabies vaccination.
• For rabbits. No rabies shot needed, but a CVI is still required.

It might seem like red tape, but it helps Colorado prevent the spread of diseases. If you skip this step and are stopped at a state border inspection station or caught in a local enforcement sweep (especially around airports or agricultural areas), your pet could be quarantined — and the cost of this falls on you.

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Unlicensed Livestock

Colorado has a strong agricultural economy, so livestock regulation is taken seriously for animals entering the state. Most livestock entering Colorado legally must have:

• A CVI
• Species-specific testing (such as a Coggins test for horses)
• A livestock movement permit, depending on the species and origin state
• Possibly a brand inspection, especially for cattle and horses

Species that fall under Colorado’s livestock regulations include:

• Cattle, pigs, goats, and sheep
• Horses, mules, and donkeys
• Poultry (yes, even a few backyard chickens)
• Llamas, alpacas, and bison

If you’re not sure whether your animals qualify as livestock, check with the Colorado Department of Agriculture. And remember — many exotic or uncommon animals may also fall under wildlife import laws, which are even stricter.

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Restricted Firearms

You’re allowed to bring most legally owned firearms into Colorado, but there are a few firm exceptions. These include:

• Machine guns, and any parts that convert a firearm to automatic fire
• Short-barreled rifles and shotguns (barrels under 16 inches and 18 inches, respectively)
• Suppressors/silencers, unless federally registered and approved
• High-capacity magazines that hold more than 15 rounds, unless owned prior to July 1, 2013

If you’re moving from a state with looser gun laws, be aware that bringing any of these into Colorado could result in criminal charges.

What you can bring:

• Handguns and long guns that comply with federal and state laws
• Ammo within normal quantity and type limits
• Concealed carry weapons if your out-of-state permit is recognized in Colorado

Colorado has a statewide concealed carry reciprocity system — your permit is valid only if your state honors Colorado’s. If not, you’ll need to reapply once you become a resident. Also, keep in mind that Colorado cities such as Denver may have their own, stricter firearm laws. So always check local ordinances before you move.

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Some Dangerous Weapons

Beyond guns, Colorado prohibits a number of so-called dangerous weapons that frequently show up in moving trucks without the owner realizing they’re banned, such as:

• Brass knuckles (metal or hard plastic)
• Blackjacks, sandclubs, and leaded batons
• Ballistic knives (knives that fire a blade)
• Explosive or incendiary devices
• Gas guns and tear gas launchers

Possessing these items in Colorado is against the law, and crossing the border with them may lead to misdemeanor or felony charges, depending on the weapon. These classifications and penalties are detailed in Colorado Revised Statute 18‑12‑102, which defines what the state considers dangerous or illegal weapons.

On the other hand, there are some weapons that are generally okay to bring with you:

• Hunting knives and bows
• Standard utility blades
• Pepper spray for personal defense
• Pocketknives with blades under 3.5 inches in length

If you’re not sure whether something is allowed, it’s safer to leave it behind—or contact law enforcement at your destination before you load it into the moving truck.

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Fireworks

In Colorado, many common fireworks are illegal — even if you bought them legally elsewhere. The line between legal and illegal comes down to whether they explode or leave the ground. According to Colorado law (C.R.S. 24‑33.5‑2002), any fireworks that meet either of those criteria are banned statewide, while non‑explosive, ground‑level types are generally allowed unless restricted by local ordinance.

For example, these fireworks are illegal to bring into Colorado:

• Roman candles
• Firecrackers
• Bottle rockets
• Aerial shells

These types are usually legal (but it varies locally):

• Sparklers
• Smoke bombs
• Ground spinners
• Cone fountains

Many cities, especially in high fire-risk areas like Boulder or Colorado Springs, ban personal fireworks entirely. So even items allowed at the state level may not be permitted depending on your destination.

To stay safe and legal, plan to attend a public fireworks show and leave your own stash behind.

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Open Containers of Alcohol

You can’t have an open container of alcohol in the passenger area of a moving vehicle, whether you’re driving a rental truck, a personal car, or a moving van. An open container is:

• Anything with a broken seal
• Partially consumed beverages
• Previously opened bottles, even if resealed

The safest way to transport alcohol is to keep it unopened or place it in the trunk or far rear of the vehicle. You’re allowed to bring your alcohol collection with you when you move — but treat it as you would a toolbox; stowed securely and out of reach.

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Open Marijuana

Recreational marijuana is legal in Colorado, but interstate transport isn’t. Even if you’re coming from another state where cannabis is legal, you can’t bring it with you across state lines. This includes flower, edibles, vape pens, tinctures — anything with THC.

Once you’re inside Colorado, you can legally:

• Possess up to 1 ounce of flower (or equivalent in other forms)
• Carry factory-sealed marijuana containers in your vehicle
• Grow up to 6 plants per adult in your household (with some local limits)

But, much like alcohol, open containers of marijuana are not allowed in any area of a vehicle accessible to the driver or passengers. That includes opened edible packaging, partially smoked joints, or anything with a broken seal. To comply with state law, any open or previously used marijuana products (purchased legally within Colorado) must be stored in the trunk or another out-of-reach area, and should never be used while driving.

 

“…[R]ainwater collection has historically been restricted here, but the law recently changed. As of 2025, there’s no longer a statewide limit on how much rainwater you can collect…”

 

If you’re moving from another legal state, your best option is to consume or dispose of your cannabis before crossing into Colorado, then restock legally at a licensed dispensary after you arrive.

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Other Legal Things to Check If You’re Moving to Colorado

The following laws are worth knowing so you don’t get caught off guard in your first few weeks as a Coloradan. They might seem minor, but missing a deadline or overlooking a quirky regulation can lead to fines, extra paperwork, or just unnecessary stress during an already hectic time.

Colorado Driver’s License and Car Registration

Once you become a Colorado resident (by living here for 90 consecutive days, taking a job, or registering your kids for school), you’ll need to:

• Transfer your driver’s license within 30 days
• Register your vehicle within 90 days

You’ll need:

• Proof of address
• Your old license and registration
• Proof of Colorado insurance
• Emissions test results (in applicable counties)

If you miss these deadlines, expect late fees—and possibly a backdated tax bill.

Rainwater Collection Laws

If you’re moving to Colorado from out of state, this might surprise you — rainwater collection has historically been restricted here, but the law recently changed. As of 2025, there’s no longer a statewide limit on how much rainwater you can collect, as long as it’s done properly and used for specific outdoor purposes.

Here’s what to know if you’re planning to install a collection system after your move:

• Rainwater must be collected from your own roof, not shared buildings or structures.
• It can only be used for non-drinking outdoor purposes, such as watering a garden or landscaping.
• Collection systems must be closed and secure—no open barrels that could attract mosquitoes.
• Local governments may have additional restrictions or permitting requirements.

Colorado now allows more flexibility, but it’s not a free-for-all. If sustainable living is part of your move, check with your county or visit ColoradoDNR.gov to make sure your setup follows the latest rules.

Mountain Driving and Traction Laws

Colorado’s mountains are breathtaking—and treacherous in the winter. From September through May, traction laws apply to many roads, especially I-70.

You must have:

• All-wheel drive OR
• Snow tires with 3/16-inch tread depth OR
• Chains or traction devices

If you’re caught without proper traction gear during a storm, you could face steep fines, so make sure your vehicles are winter-ready.

Sunday Car Sales Ban

Planning to buy a car after your move? You’ll need to do it Monday through Saturday. Car dealerships in Colorado are legally required to close on Sundays. It’s an old law that still stands statewide.