Google has a setting in Webmaster tools which help webmaster to help Google understand your target location. This will help Google presenting your site in that location's search result. In other way this will get you more targeted visitors free of cost.
I read interesting theory of Google concept of geo information of your website. Google will make geographic associations based on top level domain or web master's IP address from where these context was served, if no information is provided in Webmaster tools.
Setting for this in Google webmaster tools: Google WebMaster Tools -> Site Configuration -> Settings -> Geographic target.