Translation:The US is bigger than Japan.
Using 「方」 and 「よる」 http://www.guidetojapanese.org/learn/grammar/comparison
I didn't see it here so I will write it. This way of comparing was weird for me at first, because I learnt is differently. And after asking for informations, I found out a few things : First, の方 doesn't need to be here. In conversation, you can just say より. 方 emphasizes the subject. Second, you can move 日本より just before the adjective. With all that it can become : アメリカ は日本より大きいです。 If you add again の方 : アメリカ の方が日本より大きいです。hope it will help.
Hm... I'll allow myself to nitpick on what you said.
The より itself in this context means something like "than": "B is *** than A." Japanese does have a verb for "compare", it's 比べる (くらべる) and it's used pretty often:
日本に比べると、アメリカのほうが大きいです。Compared to Japan, the USA is bigger.
ほう in this case is what is called a formal noun (keishiki meishi), which means it's serving a grammatical purpose in the sentence and should not be written in kanji. Some Japanese people still choose to write formal nouns in kanji, so you can always submit an error report and see if the contributors decide to add it.