Every time, when you set Google.com as your homepage, once you open up your browser, you will be automatically redirected to your google local page.
Unless your current location is US IP address, else you won’t get Google.com as your homepage.

By default, Google will automatically redirects your Google.com homepage to a local Google homepage of a country, such as for example Google.com.sg for Singapore. Google did that because it wants to provide relevant search results to users by countries.

But then, if you still want to set your homepage as Google.com to search on Google.com directly, here’s a quick tip you could use.

Just use either one of the links below as your homepage:
http://www.google.com/ncr
http://www.google.com/webhp

After that, you can re-launch your browser, you will see that your Google.com homepage won’t redirect to your local Google domain again.

Enjoy your Google.com browsing experience!