Final answer:
The area marked X on a historical map could be part of the Northwest Territory, the Louisiana Purchase, the Mexican Cession, or the Oregon Territory; identifying it requires examining the map's specific date and geographic context with historical information as a reference.
Step-by-step explanation:
The area marked X on the map could be part of one of several historical land acquisitions or territories in United States history. These include the Northwest Territory, established by the Northwest Ordinance of 1787, the Louisiana Purchase in 1803, the Mexican Cession following the Treaty of Guadalupe Hidalgo in 1848, and other territories such as the Oregon Territory. Determining which area X represents would require examining the specific map and its historical context, such as the date of the map and the geographic boundaries shown at that time. Information provided from sources-like LibreTexts, which shows the extent and nature of these territories-would be vital to making this determination.