Stream of consciousness rationale: The relevant information is: The treaty came into force on July 4, 1848.
The question and answer pair are described below.
Q: The Treaty of Guadalupe Hidalgo (Tratado de Guadalupe Hidalgo in Spanish), officially titled the Treaty of Peace, Friendship, Limits and Settlement between the United States of America and the Mexican Republic, is the peace treaty signed on February 2, 1848, in the Villa de Guadalupe Hidalgo (now a neighborhood of Mexico City) between the United States and Mexico that ended the Mexican -- American War (1846 -- 1848). The treaty came into force on July 4, 1848.

Answer this question based on the passage: when did the treaty of guadalupe hidalgo happen?
A: July 4 , 1848