By using the political theory of Manifest Destiny, Americans thought they had the right to expand their land in order to spread democracy. Leading up to the Mexican-American War, the U.S. tried to acquire lands from Mexico. After Texas was annexed in 1845 and the Rio Grande River was made the border between it and Mexico, the government commissioned explorations into this newly acquired land. Bryant Tilden’s Notes on the Upper Rio Grande, written in 1847 and published by Lindsay and Blakiston, is a travel journal written to survey the Rio Grande River in order to determine the possibility of military steamboat transportation. This book details the encounters between Tilden and the Mexican people, with a lithograph map by Thomas Sinclair. This paper argues that Bryant Tilden’s Notes on the Upper Rio Grande misrepresents Mexicans in order to justify U.S. superiority. By using postcolonial theory and the theory of orientalism, I will examine the text and images in Bryant Tilden’s Notes on the Upper Rio Grande in order to analyze how these misrepresentations of Mexicans were made.