Chipmunks build and live in complex burrows which have several entrances, tunnels and chambers for sleeping which are kept very clean. Shells and faeces are stored in refuse tunnels. Sleeping areas are enlarged and filled with shredded leaves to make a comfortable bed. Food is normally stored in the lowest tunnels, to keep it cool and fresh.
Photograph by Akhil p Chandra (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons