This document discusses migration to the United States. It provides background information on migration, a brief overview of the US, and examines the impacts of migration on environmental, social, economic, and political issues in the US. Specifically, it notes that immigration contributes to US population growth, which impacts the environment. It also discusses how contact with immigrants can shape Americans' views of them, and how Hispanic immigrants have been affected by economic downturns. The document concludes that migration to the US is generally positive but should have appropriate boundaries and security measures.