How does google know what city I live in?

like if i type in something... almost anything... ill use the random phrases: play dough, good food, seafood, cheap video cameras, cheap wallets, used toasters, kitchen blenders... candy.... roller rinks.... it know my city and state and stuff in my area... so if i type in something like white castle... the search suggests my zip code, state or city or both... and gives all the phones numbers to white castles in my area.... how do i get rid of this? there is a part that says my city and asks me if i want to change my location... but it wont let me disable it and says it "auto detects".... and i don't have google toolbar... so it says its using MY IP ADDRESS??!?!?! this is creepy... its creepy enough that they give me ads that relate to things iv googled in the past... every ad is something iv googled.... how can i disable this stuff or is their nothing i can do about it?