Do you space between the abbreviation for United States?

The correct way to write the abbreviation for the United States is U.S. with a period after each letter.

No space is needed between the letters.

However, there is an exception when it is used as an adjective. In that case, it is written as U.S. without periods.

For example:

* U.S. history (adjective)

* The U.S. is a large country. (noun)