The Netherlands actualy
I live in a small village with 11 gyms and about 20 Pokéstops I guess. Well more actually since gyms are Pokéstops these days.
I am lucky to be part of the Mystic team but still it's hard to level and earn 50 coins a day.
Sometimes I visit a big city and if I should live over there I would have been level 40 easily. It's non stop catching and hatching then.