Answer:
Methodist and Presbyterian missionaries established settlements
Lewis and Clark explored and mapped the interior.
John Jacob Astor made one of the first settlements.
Explanation:
The Oregon Territory was initially an extension of land owned by America until February 14th, 1859 when it was officially recognised as the State of Oregon and part of the Union.
Therefore, the three events that the United States used as a claim to the Oregon Territory are
Methodist and Presbyterian missionaries established settlements
Lewis and Clark explored and mapped the interior.
John Jacob Astor made one of the first settlements.
