There is no national leash law. There are thousands of local ones.

Leash requirements in the United States are set almost entirely at the local level. A state may set a baseline — for example, requiring dogs to be under control or restrained in certain situations — but the everyday rule you meet in a park is usually a city or county ordinance, often found in the municipal code under “animals” or “animal control.”

Typical elements of a local leash ordinance:

• A general leash requirement in public places, frequently with a maximum leash length (six feet is common, but not universal).
• Designated exceptions — fenced dog parks, posted off-leash areas or off-leash hours in specific parks.
• “Voice control” or “under control” standards that apply inside off-leash areas and define what the exception actually requires of you.
• Waste, licensing and vaccination requirements that apply regardless of leash status.

On top of the municipal rule, the land manager may add its own. State parks, National Park Service units, National Forests, and regional park districts each publish pet rules, and those rules can be stricter than the surrounding city's ordinance — on many National Park trails, for example, pets are either prohibited or must be on a leash no longer than six feet.

An off-leash designation is an exception to the leash rule, not an exemption from control. In most jurisdictions it still requires that your dog:

• responds reliably to voice commands and stays within your sight;
• is currently licensed and vaccinated as the jurisdiction requires;
• is leashed when entering and leaving the area, and in any transition zone;
• is removed if it shows aggression, and that you pick up after it immediately.

Many areas also restrict dogs in heat, very young puppies, or the number of dogs one handler may bring, and some operate separate sections for small and large dogs. Posted hours matter: an “off-leash hours” park is fully on-leash outside those hours.

Leash violations are usually civil infractions or misdemeanors under the local code, dealt with by animal control or park rangers through a citation. Fine amounts are set locally and vary widely — from tens of dollars for a first offense to several hundred for repeat violations — and they often rise sharply if an off-leash dog injures a person or another animal. Beyond the fine, an incident can trigger dangerous-dog proceedings under state law, which carry far more serious consequences.

• Identify the jurisdiction. City limits and county land can sit side by side; the park's own page usually names the managing agency.
• Search the municipal code. Most cities publish their code online; search the animal-control chapter for “leash,” “restraint” or “at large.”
• Check the parks department separately. Off-leash areas and hours are typically listed by the parks agency rather than in the ordinance itself.
• For state and federal land, read the pet policy of the specific unit — rules differ between a national park, a national forest and a state park even when they adjoin.
• Read the sign at the trailhead or gate when you arrive; temporary closures for wildlife, fire risk or maintenance are often posted only there.

On DogSphere, place pages show the recorded off-leash status, the source it came from, and any local rule summary we hold for that locality. Where we have no source, the page says so rather than implying dogs may run free.

• Carry proof of rabies vaccination. Most jurisdictions require it, and some off-leash areas require a visible current tag.
• Expect the rule to change when you cross into a new city or county, even on the same trail system.
• Check seasonal wildlife closures — beaches, dunes and shorelines commonly restrict dogs during nesting season, and some coastal parks require leashes year-round.

• Pets in national parks — National Park Service
• 36 CFR § 2.15 — Pets (National Park System regulations) — eCFR
• Rabies prevention and control — Centers for Disease Control and Prevention

This guide explains how the framework works; it is not legal advice. The rule for any specific park is set by the city, county, state or federal agency that manages it — always confirm locally.