Location of Mozilla Firefox history

C:\Users\<username>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile folder>
C:\Users\<username>\AppData\Local\Mozilla\Firefox\Profiles\<profile folder>\cache2 /Users/<username>/Library/Application Support/Firefox/Profiles/<profile folder>
/Users/<username>/Library/Caches/Firefox/Profiles/<profile folder>/cache2 /home/<username>/.mozilla/firefox/<profile folder>
/home/<username>/.cache/mozilla/firefox/<profile folder>/cache2

Up to version 31 the cache files were stored in a folder named 'Cache'. Starting with version 32 the cache files are stored in a folder named 'cache2'.

Format of Mozilla Firefox history

Firefox Bookmarks are stored in the 'places.sqlite' database, within the 'moz_bookmarks' table. Associated URL information is stored within the 'moz_places' table. Firefox Browser Settings are stored in the 'prefs.js' file. Firefox Cache is stored using a Cache Map File ('_CACHE_MAP_'), three Cache Block files ('_CACHE_00#_'), and a number of separate data files. The cache structure was changed in Firefox version 32 and named 'Cache v2'. Firefox Cookies are stored in the 'cookies.sqlite' database, within the 'moz_cookies' table. Firefox Downloads are stored in the 'places.sqlite' database, within the 'moz_annos' table. Associated URL information is stored within the 'moz_places' table. Older versions of Firefox stored Downloads in a separate 'downloads.sqlite' database, within the 'moz_downloads' table. Firefox Favicons are stored in the 'favicons.sqlite' database, within the 'moz_icons' table. Older versions of Firefox stored Favicons in the 'places.sqlite' database, within the 'moz_favicons' table. Firefox Form History is stored in the 'formhistory.sqlite' database, within the 'moz_formhistory' table. Firefox Logins are stored in the 'logins.json' file. Older versions of Firefox stored Logins in a 'signons.sqlite' database, within the 'moz_logins' table. Firefox doesn't explicitly store Searches however they can be extracted from URLs within Website Visits, Session Data, Cache Records and Favicons. Firefox Session Data is stored in JSON format within the 'sessionstore.jsonlz4' file. Firefox Thumbnails are stored as individual PNG files within the 'thumbnails' folder. Firefox Website Visits are stored in the 'places.sqlite' database, within the 'moz_historyvisits' table. Associated URL information is stored within the 'moz_places' table.