Border

Borders are the boundaries seperating the Clan territories (either separating two Clans, or a Clan and a neutral territory). They are usually defined along geographical features, such as rivers like the one between ThunderClan and RiverClan or Thunderpaths such as the border in the forest between ThunderClan and ShadowClan. Borders are normally checked and marked twice daily by patrols. Crossing a border into another Clan's territory without acknowledgement from the other clan is considered breaking The Warrior Code, considering that it a cat could be spying or stealing prey.

In The Forest

 * ThunderClan shared borders with RiverClan (along the river) and ShadowClan (along a Thunderpath)
 * As ShadowClan was on the opposite side of the Thunderpath, it shared borders with only ThunderClan (along the aforementioned Thunderpath)
 * RiverClan shared borders with ThunderClan and WindClan; both borders were along the river
 * WindClan shared a border only with RiverClan, along the river that flowed in a gorge


 * Note: The Thunderpath was built some time after the Clans moved in. Before it was constructed, there was no fixed border, and the Clans always fought over territory.

At The Lake

 * ThunderClan shares borders with WindClan (the stream leading to the Moonpool) and ShadowClan (a part of a stream, a clearing, then going straight towards the hills)
 * ShadowClan shares borders with RiverClan (a small Thunderpath leading to a Greenleaf Twolegplace) and ThunderClan (described above)
 * RiverClan shares borders with WindClan (the marshes and the Horseplace) and ShadowClan (the small Thunderpath)
 * WindClan shares borders with ThunderClan (the stream) and RiverClan (the marshes and the Horseplace)

Protection
Patrols check and mark the borders to ensure they haven't been crossed and make sure they are clear. Clans normally patrol their borders two times a day, at dawn and at sunset, unless more are needed due to danger or in some cases less, like in Twilight when there was the danger of the kittypets.

Crossing the Border
Unless a cat is allowed by an other Clan to enter their territory, crossing the border is a sign of aggression that often leads to battle. The Clan finding intruders in its territory usually attacks them or chases them out. However, at the lake, cats are allowed to travel three tail-lengths away from the water if they are on an important mission, or traveling to the Clans' monthly Gathering

Examples
Needing Help
 * Mistyfoot crossing over the ShadowClan and ThunderClan border in Starlight at the lake because of her suspicions about Hawkfrost and Mudclaw.
 * Hollypaw crossed over the ShadowClan border in Eclipse at the lake when WindClan attacked.
 * Fireheart and Graystripe crossing the RiverClan border to give fresh-kill to RiverClan, in the forest in Forest of Secrets.

Attacks/Invasions

 * WindClan coming through the tunnel to attack ThunderClan in Eclipse at the lake.
 * ShadowClan and WindClan crossing ThunderClan's border to attack ThunderClan for sheltering Brokentail in Forest of Secrets.

Other

 * The RiverClan patrol in Dark River was chased over the border by the Twoleg dog, Pip.
 * Tigerstar crossing the ThunderClan border in the forest to feed a pack of dogs in A Dangerous Path .
 * Fireheart crossing the WindClan border to go find WindClan in Fire and Ice.