The smallest US state by total encompassed area is Rhode Island (1545.05 sq. mi.)
The smallest US state by land area (excluding encompassed bodies of water such as lakes and harbors) is still Rhode Island (1044.93 sq. mi.). Rhode Island has the highest percentage of area being water (32.37%), of all states in the continental US.
The smallest US state by population is Wyoming (563,626 people). (Hah! As of the 2010 census, Rhode Island ranked 45th in population!)