Final answer:
A territory could apply for statehood under the Northwest Ordinance of 1787 once it had more than 60,000 white male inhabitants, adopted a constitution prohibiting slavery and ensuring religious freedom, and received Congressional approval.
Step-by-step explanation:
Under the Northwest Ordinance of 1787, a territory could organize and apply for statehood once it reached a population of over 60,000 white male inhabitants. At that point, the territory could adopt a constitution, which had to include the stipulation to forbid slavery and ensure religious freedom, before applying for statehood, which would then need to be approved by Congress. The passage of the Northwest Ordinance was a significant step both for territorial organization and for the establishment of policies regarding slavery and the rights of settlers in what would become the future states of Illinois, Indiana, Michigan, Ohio, Minnesota, and Wisconsin.