Pocket knives are small, folding knives that can fit in a pocket. They are used primarily as tools and are generally legal to own and carry. Knife laws vary widely by state, however, as do definitions of what is considered a “pocketknife.”

In the United States in 2026, the legality of folding pocket knives is a complex patchwork of state and local laws rather than a single federal rule. Generally, a non-locking folding knife with a blade under 3 inches (like a standard Swiss Army Knife) is legal to carry in almost every state. However, "pro" legal issues arise once the blade exceeds 3.5 or 4 inches, or if it has a locking mechanism. In 2026, states like Texas and Arizona have virtually no restrictions on blade length or type, whereas New York City and Chicago have extremely strict ordinances; in NYC, for instance, carrying a knife where the pocket clip is visible is a violation, and "gravity knives" or those that can be opened with a "flick" remain highly scrutinized. Furthermore, even a "legal" knife is strictly prohibited in Restricted Zones, including schools, government buildings, courthouses, and past airport security checkpoints. Before traveling, it is essential to check the specific city ordinances of your destination, as a tool that is perfectly legal in a rural setting can lead to an "unlawful possession" charge in a metropolitan transit hub or a federal facility.