The West cannot be precisely defined in terms of where it is or its definitions. A rough starting point would say that it is where rich, white people live in multicultural, liberal societies, imbued with Judeo-Christian values tempered with renaissance thinking, and pragmatically transformed by the effects of the industrial and neo-liberal revolutions.
But where would that put Hungary, or Nazi Germany, or Singapore, or Chile, or South Central Los Angeles, or the Bible Belt?
The concept of the West has changed considerably over history anyway:
Before Christopher Columbus, The West was everything west of a diagonal line from Moscow to Salonika. Feudal exploration led to contact and ultimately settlement in Siberia, the Americas and other parts of the world. In Europe around the 1500s a mordernising core emerges in Italy, France, north Germany, along the Danube and English Channel and Saint Petersburg. Nation states also emerge, promoting the concept of citizenship over basing societies on ethnic or religious lines. Eventually this leads to Europe dominating the rest of the world through its economic, military and scientific ascendancy.
From this the technology and economic base emerges that allows European states to accelerate and sustain colonialism, and trigger the start of the Industrial Revolution. Concepts of liberal democracy emerge, leading to the downfall of autocratic political structures. The arts and literature likewise influenced and were influenced by people rethinking their relationships with their God, their kings and themselves.
Western values appeared promoted individualism over the loyalty to the family, clan or state. Some rulers in the West were thus naturally reactionary to this idea. Some reformed their political systems, others ended up loosing control altogether in bloody revolutions. Totalitarianism reemerged as a reaction to individualism, leading to World War II. Subsequently many Western countries relinquished their colonies, but their technology, human capital, political stability and financial strength made them remain economically potent. In particular, the West's individualism and separation between culture and politics has made it possible to attract and absorb immigrants from all over the world.
Various international groupings like the European Union, the Commonwealth, ANZUS and NATO give us a very rough idea where the elusive West exists. These societies are based on democratic values, human rights and property rights. But if you were a true Westernist (note that the word does not exist for a good reason) you would say that Westernism is merely a semantic construct, and that hypocritically it has its own dark episodes.
The heterogenity of the West makes it hard to define. The French adamantly consider their society is distinct from the Anglo-Saxons. Mediterranian family values might look similar to Asian ideals of the extended family. As Margaret Thatcher said, societies do not exist, only individuals exist. | 
