How the data is built, where it comes from, and how we keep it from going stale.
We never guess a dog policy. Every rule on this site is taken from the agency that actually manages the land, and if we cannot confirm a policy from an official or clearly reliable source, we leave that place out rather than publish a guess.
The dog policy for each national park and NPS unit (seashores, monuments, historic sites, and recreation areas) starts from the National Park Service pet page for that unit, linked on every page. Permissive units and any place where access varies trail by trail were checked individually.
National forest policies come from the U.S. Forest Service, BLM units from the Bureau of Land Management, and refuges from the U.S. Fish and Wildlife Service. Refuges especially vary a lot, since they protect wildlife first, so each one was checked against its own fws.gov page.
Each state park system has one baseline policy, which we verify at the system level. On top of that, we build individual pages for the parks people search for and, importantly, the ones with a distinctive rule: a ban, a seasonal beach closure, an off-leash area, or a nature-preserve restriction. We deliberately do not create a page for a park that only repeats the statewide default, since a page that adds nothing is not worth your time.
Beach rules are set by cities, counties, states, or the Park Service depending on the beach, so each one is verified against whichever official body sets the rule. Seasonal closures for nesting birds are called out because they catch people off guard.
Every page carries the date we last checked it against the source. Pages are re-verified on a regular cycle, and any reader-flagged change gets checked right away.
We do not invent trail counts or mileages, we do not fake hands-on testing, and we do not bury the official source. Where a rule is a general policy rather than a park-specific detail, we keep the wording general on purpose.