The Northwest portion of America was in dispute between the English and the United States for many years. The opening of the Oregon Trail in 1842 brought a great influx of American settlers into the area and this led to the Treaty of Washington in 1846 and the area became a part of the United States. In 1848 Oregon became a Territory and in 1859 it became the 33rd state in the United States. The first census was taken in 1850 while it was still a Territory.