Australia isn’t; and coming from the Bush (not the Outback’s much more expansive options) the possibilities are both more frequent and of greater scale.
Doing some chores on one of the family farms when the rest of the family were off the property would have put an exclusion zone of 10-12km, assuming the neighbours were also home.
But for an assured sense of isolation, (as I have posted before) when travelling home one route was via Steam Plains Road where a one point you had a 360 degree view of the horizon without seeing any sentinent life-form, man-made structure, hill or hollow or tree for that matter. So that would be about 7km and likely close to the maximum assured distance possible.