Due in large part to the persuasion of representative Servando Teresa de Mier, Mexico City was chosen because it was the center of the country's population and history, even though Querétaro was closer to the center geographically. The choice was official on November 18, 1824, and Congress delineated a surface area of two leagues square (8,800 acres) centered on the Zocalo. This area was then separated from the State of Mexico, forcing that state's government to move from the Palace of the Inquisition (now Museum of Mexican Medicine) in the city to Texcoco. This area did not include the population centers of the towns of Coyoacán, Xochimilco, Mexicaltzingo and Tlalpan, all of which remained as part of the State of Mexico.
When was Mexico City declared the capital? (If the question is unanswerable, say "unanswerable")
November 18, 1824