This is half of the first paragraph of the simplified Chinese entry for the United States in Wikipedia. I cheated a bit to bring it under length: the 英文 portion actually spelled out United States of America. It clocks in at about 138 characters.

A rough translation from someone who is not literate in Chinese just to show you the information density:

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The United States of America (English: USA), referred to commonly as the United States, formerly known as the United States [editor's note: anachronistic Chinese 花旗國 rather than 美國], consist of 50 states and one federal district, forming a constitutionally established federal republic. The United States is located in the center of North America, bounded on the east by the Atlantic Ocean and in the west by the Pacific Ocean, on the north by Canada and the South by Mexico and the Gulf of Mexico. The capital is Washington, DC. It is comprised of Hawaii, Alaska, and the 48 contiguous states.

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[Edit: I was curious so I checked in Japanese, too, to substantiate my feeling that it would be at the midpoint between Chinese and English. Yep.

アメリカ合衆国（アメリカがっしゅうこく、英：United States of America）、通称アメリカまた合衆国（合州国）、米国（べいこく）は、北アメリカ大陸および北太平洋に位置する連邦共和国。 イギリスの北米植民地が1776年7月4日に独立を宣言して成立した国家である。

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The United States of America (insert pronunciation guide in Japanese here, English: United States of America), usually referred to as America, the United States (the US), or another way to say the US in Japanese is a federal republic located on the North American continent and in the north Pacific Ocean.

The United States of America was founded a nation when the North American colonies declared their independence from England on July 4th, 1776.]

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And, for the comparison to English, here is what fits in a Tweet:

The United States of America (commonly referred to as the United States, the U.S., the USA, or America) is a federal constitutional republic

There wasn't enough space for the period.