Urban areas are defined as those areas dealing with cities or industrialized conditions.
Over time the makeup of the earth has become more urban. In the United States, while urbanization has increased over time, there has also been a parallel trend towards moving away from urban areas to suburban or rural locations since urban areas have many issues from crowding, to crime, to pollution. As with many things, where one lives is often a sign of social status and cultural stand. There is a tendency for so-called urbanites to be more liberal, and more suburbanites to be more conservative. But like all things, this is merely a tendency and does not mean any given person who lives in a particular area will be liberal or conservative, religious or non-religious, etc.