Castleguard Cave
（重定向自Castleguard）
![The entrance to Castleguard Cave in summer. Note the substantial amount of water coming from the cave mouth.](/Images/godic/202501/03/Enterance_to_Castleguard4159.JPG")
![Flagged soda straws, Castleguard Cave.](/Images/godic/202501/03/Castleguard_flags4159.jpg")
![Second Fissure, Castleguard Cave.](/Images/godic/202501/03/Castleguard_secfiss4159.jpg")
Castleguard Cave is a limestone cave located at the north end of Banff National Park in the Rocky Mountains of Alberta, Canada. With 20,357m of surveyed passages (as of 2007), it is Canada's longest cave, and its fifth deepest at 384m. Castleguard Cave ascends gently from its entrance and terminates beneath the Columbia Icefield.