This collection contains congressional publications from 1774 to 1875, including debates, bills, laws, and journals.

President James Polk submitted a message to Congress outlining his reasons for declaring war with Mexico.

Messages of the President of the United States, with the correspondence, therewith communicated, between the Secretary of War and other officers of the government, on the subject of the Mexican War (H.exdoc.60)

The House of Representatives approved a resolution declaring war with Mexico by a vote of 174 to 14.

The Senate approved a resolution declaring war with Mexico by a vote of 40 to 2

President Polk signed "An act providing for the prosecution of the existing war between the United States and the Republic of Mexico".

The Treaty of Guadalupe Hidalgo was signed by the United States and Mexico.

The Senate ratified the Treaty of Guadalupe Hidalgo by a vote of 38 to 14.

In honor of the 150th anniversary of the treaty signing, the Hispanic Division at the Library of Congress created an online exhibit on the Treaty of Guadalupe Hidalgo. The exhibit it includes page images of the original treaty housed in the Library of Congress Manuscript Division and the area map used during the negotiations from the Geography and Map Division.

The Library of Congress has custody of the largest and most comprehensive cartographic collection in the world with collections numbering over 5.5 million maps, 80,000 atlases, 6,000 reference works, over 500 globes and globe gores, 3,000 raised relief models, and a large number of cartographic materials in other formats, including over 19,000 CDs/DVDs.

A telegraph announcing that Mexico City was captured and an armistice was signed.

General Zachary Taylor defeated a detachment of the Mexican army in a two-day battle at Palo Alto and Resaca de la Palma on May 8, 1846.

The Battle of Buena Vista was won by the United States on February 23, 1847. General Zachary Taylor, future president of the United States, was the commander of American troops in this victory over Mexican General Antonio Lopez de Santa Anna.

The Treaty of Guadalupe Hidalgo was signed in Mexico City on February 2, 1848.