Sentence:  When in 1816 an act of Congress forced the foreign firm out of the <WSD>United</WSD> States , its British born employees , now become American citizens - Joseph Rolette , Joseph Renville and Alexis Bailly - continued in the fur business . 
Meaning of the word marked with <WSD> tags:  North American republic containing 50 states - 48 conterminous states in North America plus Alaska in northwest North America and the Hawaiian Islands in the Pacific Ocean; achieved independence in 1776