Google will always provide the results that we believe are most relevant to your search.Location is one of a number of factors that we use to provide these relevant results.For example,if you search for a restaurant chain,you may want to find one near you.when searching for movie showtimes,you may want listings in your area.Such search resutls are made possible by location-based customization.
The location used to customize your results is clearly indicate on the left side of your results page.our location detection technology will automatically for you,or you can specify an alternate location.

Automatically detected location
To provide you with the most relevant results,Google attempts to automatically detect your location and customize results based on that detected location.A location A location that's labeled "Auto-detected" is chosen
based on the following factors:
  • Your IP address .
  • Google Toolbar's My Location feature. If you have Google Toolbar installed and have the My Location feature enabled, your approximate location (if detected) will be used to customize your search results. If you don't want Toolbar to attempt to determine your approximate location, you can turn off My Location

Official Google Blog: More transparency and control over location