- How did the United States gain the Northwest Territory? a in a war with Mexico
b. as part of the Treaty of Paris
C. in a war with Canada
d by buying it from France

The embargo act of 1807  was a law passed by the united state congress and signed by president thomas jefferson on december 22,  1807. it prohibited american ships from trading in all foreign ports. in 1806, france passed a law that prohibited trade between neutral parties, like the u.s., and britain.