Boonies, short for boondocks, usually refer to someplace remote or rural . . . like where I grew up . . . waaaaaaaaaaay out in the sticks.
The origin of 'boondock' is simple and straightforward but interesting, nonetheless.
The word was adopted by American soldiers during the Spanish-American war. The soldiers were deployed deep into the forests and mountains of the island . . . or the bundoks, as the indigenous folk would say . . . ambushing the enemy and fight small concentrated battles.
‘Bundok’ became boondock and thus became a part of conventional vernacular.