In Windows XP :
C:\Documents and Settings\UserName\Local Settings\Application Data\Google\Chrome
Local Settings folder is a hidden folder, to see hidden folder go to tools -> Folder Options -> View tab -> and make sure show hidden files and folders is checked.
In Windows Vista
C:\Users\UserName\AppDataLocal\Google\Chrome
AppDataLocal folder is a hidden folder, to see hidden folder go to tools -> Folder Options -> View tab -> and make sure show hidden files, folders and drives is checked.
In Windows 7
C:\Users\Username\AppData\Local\Google
AppData folder is a hidden folder, to see hidden folder go to tools -> Folder Options -> View tab -> and make sure show hidden files, folders and drives is checked.
Note:
C = windows installation drive
UserName= your windows username