No because it is informal. You can't start a proper sentence with U.S. without the word The. For example, U.S. is the third largest nation in the world. However if U.S. is used as an adjective it can be. For example, U.S. troops are the best soldiers in the world.
Yes, example: "About 200 years ago, the United States of America was founded..."
The United States
July 4th, 1776 is when the United States formed.
The "T" in "treasury" is capitalized when it is part of a proper noun, like in the name of a specific treasury department or office (e.g., U.S. Treasury). Otherwise, in general use, "treasury" is written with a lowercase "t."
· Red (United States) · Rio Grande (United States)
None. United states is a country
the united states
The United States
· United Arab Emirates · Uzbekistan
united states
United States of America
· uniform · United States