How Arizona's borders were drawn: from the Mexican Cession to statehood
Grade 8 Social Studies Worksheet - Building Confidence

Circle the best answer.
Read this first
Treaty of Guadalupe Hidalgo, Article VIII (part)
Who made it: Negotiators for the United States and Mexico. When: Signed February 2, 1848. Where: Guadalupe Hidalgo, Mexico. For whom: the two governments and the Mexican residents of the ceded land. Why: to end the Mexican-American War and set the terms of peace. Excerpt (Treaty of Guadalupe Hidalgo (1848), Article VIII, English text; National Archives transcript): "…But they shall be under the obligation to make their election within one year from the date of the exchange of ratifications of this treaty; and those who shall remain in the said territories after the expiration of that year, without having declared their intention to retain the character of Mexicans, shall be considered to have elected to become citizens of the United States."
Ari reads Article VIII. A Mexican resident of the ceded land says nothing for a full year. What does the article say happens?
- The resident is treated as having chosen US citizenship
- Residents became US citizens at once, whatever they declared
- The resident keeps Mexican citizenship by default after a year
- The resident must leave the territory and sell the land
Gadsden Purchase: a State Department history
Who made it: the Office of the Historian, US Department of State. When: today. Where: Washington, DC. For whom: readers today. Why: to explain the history of US foreign relations. Summary in our words, not a quotation: A southern railroad route had to cross Mexican land, and both countries claimed the Mesilla Valley. Santa Anna, Mexico's president, did not want to sell a large part of Mexico but needed money to pay an army fighting rebellions. The treaty signed December 30, 1853 set $15 million for 45,000 square miles. The Senate, divided by strife between northern and southern states, ratified a revised treaty on April 25, 1854: $10 million for 29,670 square miles. A later dispute over the payment followed.
Bo reads that Santa Anna "needed money" to pay an army. What does that detail help explain about the Gadsden treaty?
- Why Mexico gave up its whole northern border willingly
- Why the United States wanted a southern route for a railroad
- Why the Senate cut the price and land to $10 million
- Why Mexico's president agreed to a sale he first resisted
The Mexican Cession, 1845 and 1848
Map 1, "Before the war" (1845): Today's Arizona is part of Mexico. Native nations live on the land, among them the Tohono O'odham in the south and Apache peoples to the north. Map 2, "After the Treaty of Guadalupe Hidalgo" (1848): Mexico cedes 55 percent of its territory to the United States, including most of present-day Arizona: the land north of the Gila River. The land south of the Gila River stays in Mexico. Key: orange: Mexico; blue: the United States; a dashed line: the new border. Below the maps: The Mexican-American War lasted from 1846 to 1848. The treaty, signed on February 2, 1848, ended it. The United States paid Mexico $15 million. Mexicans who stayed on the land could keep Mexican citizenship or become US citizens, choosing within one year.
Esme studies both maps. What changed for the land north of the Gila River between 1845 and 1848?
- It stayed Mexican but was opened to US settlers
- It passed from the United States to Mexico
- It passed from Mexico to the United States
- The whole of present-day Arizona passed to the United States
The Gadsden Purchase, 1853 and 1854
Map 1, "Before the purchase" (1853): The border runs along the Gila River. Both countries claim the Mesilla Valley. The United States wants a southern route for a railroad across the continent, which must pass through Mexican land. Map 2, "After the Gadsden Purchase" (1854): The border moves south. The United States gains 29,670 square miles south of the Gila River, land that becomes part of Arizona and New Mexico. Key: orange: Mexico; blue: the United States; green: the land bought in the Gadsden Purchase. Below the maps: James Gadsden and Mexico's President Antonio de Santa Anna signed a treaty on December 30, 1853, for $15 million and 45,000 square miles. The US Senate ratified a smaller, revised treaty on April 25, 1854: $10 million for 29,670 square miles. The Tohono O'odham claim ancestral lands on both sides of the new border, and Yaqui people live on both sides too.
Jun compares the 1853 and 1854 maps. Which claim do the maps support?
- The United States added Mexico's northern states to its territory
- The border moved north of the Gila River, and the United States lost that land
- The border moved south of the Gila River, adding land to the United States
- Mexico gained the Mesilla Valley when the border moved
Gadsden Purchase: a State Department history
Who made it: the Office of the Historian, US Department of State. When: today. Where: Washington, DC. For whom: readers today. Why: to explain the history of US foreign relations. Summary in our words, not a quotation: A southern railroad route had to cross Mexican land, and both countries claimed the Mesilla Valley. Santa Anna, Mexico's president, did not want to sell a large part of Mexico but needed money to pay an army fighting rebellions. The treaty signed December 30, 1853 set $15 million for 45,000 square miles. The Senate, divided by strife between northern and southern states, ratified a revised treaty on April 25, 1854: $10 million for 29,670 square miles. A later dispute over the payment followed.
Luz reads that the Senate approved a smaller treaty than the one Gadsden signed. Which statement does the card support?
- The Senate wanted the land to stay Mexican territory in the end
- The railroad route was the Senate's sole concern in the treaty
- Disputes inside the United States helped shape the final treaty
- Mexican officials forced the Senate to cut the price and land
Article IX of the treaty, summarized
Who made it: the National Archives, summarizing the treaty text. When: today. Where: Washington, DC. For whom: readers today. Why: to explain what the treaty said. Summary in our words, not a quotation: Article IX covers Mexicans who did not keep Mexican citizenship under Article VIII. They were to be incorporated into the Union, and admitted to full US citizenship at the proper time, as Congress judged. Until then, their liberty, property and religious freedom were to be protected.
Milo reads the Article IX summary. Which statement about new US citizens in the ceded land does it support?
- Their property was held by Congress until it approved their citizenship
- They received the full rights of US citizens the day the treaty was signed
- Liberty and property were protected until Congress granted full citizenship
- They had to give up their religion to be admitted as US citizens
Arizona's 1906 vote
Who made it: the Law Library of Congress, in its In Custodia Legis blog. When: February 2022. Where: Washington, DC. For whom: readers today. Why: to mark Arizona's statehood anniversary. Summary in our words, not a quotation: In November 1906 Arizona voters rejected joint statehood with New Mexico, 16,265 to 3,141. Arizona became the 48th state on February 14, 1912, the last of the contiguous states to join.
Noah reads the 1906 vote, 16,265 to 3,141. Which claim does the vote best support?
- Arizona voters opposed becoming a state in any form
- Most 1906 voters in Arizona opposed joining New Mexico
- New Mexico voters rejected the plan too, as the card shows
- It shows what the whole population of Arizona thought in 1906
Taft's 1911 veto
Who made it: the National Archives, Center for Legislative Archives. When: today. Where: Washington, DC. For whom: readers today. Why: to explain a document in its collection. Summary in our words, not a quotation: On August 15, 1911, President Taft vetoed the statehood resolution in large part because Arizona's constitution allowed the recall of judges. Source card "Arizona timeline". Who made it: the US Senate, in its States in the Senate series. When: today. Where: Washington, DC. For whom: readers today. Why: to list the steps by which states joined the Senate. Summary in our words, not a quotation: On September 9, 1850, Congress organized New Mexico Territory, which included much of present-day Arizona. A law making Arizona a separate territory passed on February 20, 1863. In December 1911 the people voted to remove the recall of judges, and after statehood the voters reinstated it. Arizona became the 48th state on February 14, 1912.
Pia reads both cards. Which chain of events do they support?
- Voters dropped judge recall in 1906, then Taft signed the resolution in 1911
- Statehood in 1912, then Taft's veto over judge recall, then voters dropped it
- Taft's veto over judge recall, then statehood, with no change in Arizona
- Taft's veto over judge recall, then voters dropped it, then statehood in 1912
The Gadsden Purchase, 1853 and 1854
Map 1, "Before the purchase" (1853): The border runs along the Gila River. Both countries claim the Mesilla Valley. The United States wants a southern route for a railroad across the continent, which must pass through Mexican land. Map 2, "After the Gadsden Purchase" (1854): The border moves south. The United States gains 29,670 square miles south of the Gila River, land that becomes part of Arizona and New Mexico. Key: orange: Mexico; blue: the United States; green: the land bought in the Gadsden Purchase. Below the maps: James Gadsden and Mexico's President Antonio de Santa Anna signed a treaty on December 30, 1853, for $15 million and 45,000 square miles. The US Senate ratified a smaller, revised treaty on April 25, 1854: $10 million for 29,670 square miles. The Tohono O'odham claim ancestral lands on both sides of the new border, and Yaqui people live on both sides too.
Tala checks the key on the 1854 map. What does the green color tell a reader about how that land became American?
- It was bought from the Native nations living on the land
- It was given up by Mexico in 1848
- It was won in the Mexican-American War
- It was bought in a purchase, not won in the war
Treaty of Guadalupe Hidalgo, Article VIII (part)
Who made it: Negotiators for the United States and Mexico. When: Signed February 2, 1848. Where: Guadalupe Hidalgo, Mexico. For whom: the two governments and the Mexican residents of the ceded land. Why: to end the Mexican-American War and set the terms of peace. Excerpt (Treaty of Guadalupe Hidalgo (1848), Article VIII, English text; National Archives transcript): "…But they shall be under the obligation to make their election within one year from the date of the exchange of ratifications of this treaty; and those who shall remain in the said territories after the expiration of that year, without having declared their intention to retain the character of Mexicans, shall be considered to have elected to become citizens of the United States." Source card "Article IX of the treaty, summarized". Who made it: the National Archives, summarizing the treaty text. When: today. Where: Washington, DC. For whom: readers today. Why: to explain what the treaty said. Summary in our words, not a quotation: Article IX covers Mexicans who did not keep Mexican citizenship under Article VIII. They were to be incorporated into the Union, and admitted to full US citizenship at the proper time, as Congress judged. Until then, their liberty, property and religious freedom were to be protected.
Zee reads Articles VIII and IX. Which sentence is a careful claim about the treaty?
- It dealt with citizenship alone and said nothing about property rights
- It gave residents a year to choose and promised to protect their property
- It protected the property of residents who moved to Mexico, not those who stayed
- It guaranteed residents equal treatment with other citizens forever