in your backyard INFORMAL
in the area where you live, or in the area of interest or activity which you are involved in or responsible for:
How would you feel about them building a nuclear power station in your backyard?
We should take a look at what is happening in our own backyard before criticizing what is taking place in other countries.
(from Cambridge Advanced Learner's Dictionary)
裏庭; なわ張り; （自分の家の裏庭のような）近い所, 勢力範囲.