Border

Boarders were how the Clans could figure where one Clan's territory ended and another bagan. Boarders are marked by patrols and in a Clan, crossing a boarder is considered breaking the warrior code and a form of invasion.

ThunderClan
ThunderClan shared boarders with RiverClan and ShadowClan in the old forest. The boarders were the River (RiverClan) and the Thunderpath (ThunderClan).

ShadowClan
Because ShadowClan was on the opposite side of the Thunderpath, it shared boarders with only ThunderClan. This boarder was the Thunderpath.

RiverClan
In the Old Forest, RiverClan shared boarders with ThunderClan and WindClan. The boarder with ThunderClan was the river.

WindClan
In the old forest, WindClan shared a boarder with RiverClan.

ThunderClan
ThunderClan shares boarders with WindClan and ShadowClan in the lake territories. The boarder with ShadowClan is a clearing and the boarder with WindClan is the stream.

ShadowClan
ShadowClan shares boarders with RiverClan and ThunderClan in their territory at the lake. The boarder with ThunderClan is the clearing and the boarder with RiverClan is the small Thunderpath.

RiverClan
RiverClan shares boarders with WindClan and ShadowClan. It's boarders are the marsh (WindClan) and the small Thunderpath (ShadowClan).

WindClan
WindClan shares boarders with ThunderClan and RiverClan in the lake territories. The boarder with ThunderClan is the stream and the boarder with RiverClan is the marshes and horseplace.

Patrols
Patrols check and mark the boarders to ensure they haven't been crossed and make sure they are clar. Unless in time of crisis, there are usually patrols at dawn, sun high, dusk, and moon high. Patrols will patrol the whole boarder with one Clan and then go back to camp or do something else (hunt, patrol another boarder, etc.)

Markers
Usually, boarders have markers that makes it easy to tell where the boarder is. It is great if the markers can be useful but they don't have to be.

Crossing the Boarder
Unless it is an emergency, crossing the boarder is usually a sign of agression and often leads to battle. The Clan that finds intruders over its boarder can attac them or liten to their reasons but crossing the boarder is generally against the warrior code.