In this lesson, students analyze maps, art, and primary source documents in an effort to answer the central historical question: How did Americans justify westward expansion? To begin the lesson, students will examine a painting entitled “American Progress.” Students will compare 2 maps of the U.S.: a political map from 1872 and an electoral map from 1816. Next, students examine another 1816 map; the map is unusual in that it depicts the U.S. stretching to the Pacific—decades before this actually happened! Students will read 2 passages by John O’Sullivan, coiner of the phrase “Manifest Destiny,” and answer guiding questions. A final class discussion reviews students’ answers and touches on the subject of American Exceptionalism.