Oklahoma Social Studies 8.C.9.2.A

Social Studies8th GradeContent Standards

The Standard

8.C.9: Examine the political, economic, social, and geographic changes that occurred during the period of westward movement.
8.C.9.2: Analyze the territorial growth of the United States of America and the consequences of westward expansion.

Summarize the series of events and the processes used to annex Texas, as well as acquire the Mexican Cession and the Gadsden Purchase.

Oklahoma Academic Standards for Social Studies (2026) · 8.C.9.2

Teacher's field guide

What Students Need to Do: Students put the three land gains in order. They explain how Congress admitted Texas and how a peace treaty transferred the Mexican Cession after the Mexican-American War. They explain why the United States later bought land for a southern railroad route.
What Mastery Looks Like: A student can locate each area on a map and match it to 1845, 1848, or 1854. They can name the process for each gain: a congressional resolution, a peace treaty, or a negotiated purchase.
Common Misconceptions: Students may think Texas was won in the Mexican-American War, even though it joined the United States before the war. They may treat the Mexican Cession and the Gadsden Purchase as one deal rather than separate agreements.
How to Assess It: On an exit ticket, ask students to order Texas annexation, the Mexican Cession, and the Gadsden Purchase. Have them write how the United States gained each area.

Lesson moves

Give students an outline map of the Southwest and three colored pencils; have them shade each land gain in order.
Ask students to write two sentences comparing how Texas joined the United States with how the Gadsden Purchase was negotiated with Mexico.
Give pairs seven cards: Texas independence, annexation vote, border dispute, war, peace treaty, railroad plan, and Gadsden treaty; sort and sequence them.
Place a modern map of Tucson beside a Gadsden Purchase map; have students mark Tucson and sketch a possible southern railroad route.

Free download

A ready-to-print activity worksheet aligned to 8.C.9.2.A, with an answer key for the teacher on its own page. No account needed.

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