The American Civil War, 1840–1877 · THE MAP IN JUL 1848

Map of North America in July 1848

The Cession — and the question

North America in July 1848: The Cession — and the question. The map shows who held what: The Union, Mexico, 1840–54.

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Map of North America in July 1848: The Cession — and the question. Colours show The Union, Mexico, 1840–54. — JUL 1848 · THE AMERICAN CIVIL WAR, 1840–1877

These maps are reconstructed from published sources · Cliopatria v 0.2.1 · Gadsden Purchase, 1853–1854 · Treaty of Guadalupe Hidalgo, 1848 · US Military Academy: Summary of Operations, 1846-47 · Newberry Atlas of Historical County Boundaries: historical states and territories

Source details

Cliopatria contributors / Seshat Global History Databank. Selected, combined, reprojected and corrected by Maps of History as described per layer.. CC BY4.0
US Department of State; Newberry provides the actual territory polygon and effective-date metadata.. Historical treaty evidence
US National Archives, treaty and territorial cession.. Historical treaty evidence
US Military Academy Department of History; selected geographic facts reconstructed independently, original chart retained outside distributed files.. Geographic evidence only. Source atlas index requests reprint permission; original artwork not redistributed.
The Newberry Library, Atlas of Historical County Boundaries. State/territory records unioned for the displayed date; disputed/joint territories excluded from exclusive US sovereignty.. Publisher permits commercial and noncommercial lawful reuse without fees; current terms supersede obsolete NC notice in archive

Legal US boundaries come from dated Newberry records. Secession and military control use separate source layers, while campaign corridors are educational geographic reconstructions rather than surveyed continuous fronts.

reconstruction: 1840 · reconstruction: 1845 · reconstruction: 1846 · reconstruction: 1846-12-20 · reconstruction: 1848 · vector: 1860 state-interface reference · vector: gadsden1853 · vector: us-d17470c43ba4

Layer records and reconstruction methods

On the ground

The Mexican Cession, won from Mexico in 1848, raised a question: would its soil be slave or free? The Wilmot Proviso proposed that it be free, but the Senate never agreed.
The Gadsden strip remained Mexican until the purchase of 1853–54 acquired it for a southern railroad route.

The chapters of this moment

CH 1 — Mexican–American War

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