A change in federal law effective February 22, 2010, allows people who can legally possess firearms under federal, state, and local laws, to possess those firearms in Yellowstone National Park. The new law was passed by Congress as part of the Credit Card Accountability Responsibility and Disclosure Act of 2009. Previously firearms had to be unloaded, rendered inoperable, and packed, cased, or stowed when visitors traveled through Yellowstone. The new federal law makes possession of firearms in national parks also subject to the firearms laws of the states where the parks are located. In other words, if a person can legally possess firearms under the state law in which a national park is located, the new law enables them to do so inside the park as well.

The new law has no affect on existing laws and regulations regarding the use of firearms in Yellowstone. Hunting and the discharge of a firearm in the park are still prohibited. Firearms should not be considered a wildlife protection strategy. Also, federal law continues to prohibit firearms in certain facilities, such as park visitor centers and federal office buildings, where appropriate notices are posted at public entrances.