A bridle path is a path upon which horses can be ridden. In the context of the law, bridle paths may pass through many properties, and there may be disputes as to whether or not people who don't own the property can actually legally travel the bridle path. Laws regarding bridle paths may vary from county to county, or state to state.
Often, bridle paths have easements. An easement allows people who do not own the property to use parts of the property for certain reasons. So, in the context of a bridle path, some properties have bridle paths running through them with easements that allow non-property owners to ride their horses on the bridle path. This means that people who had access to the bridle path through an easement would not be trespassers. They would be able to legally use the path.