A snow fort or snow castle is a usually open-topped temporary structure made of snow walls that is usually used for recreational purposes. Snow forts are generally built by children as a playground game or winter pastime and are used as defensive structures in snowball fights. They are also built and used for make-believe games such as "house", "store", or "community", a game where multiple forts are built in a group. Along with the snowman, it is one of the two structures commonly built by children out of snow.

An igloo, also known as a snow house or snow hut, is a type of shelter built of suitable snow.