Official websites use .gov A .gov website belongs to an official government organization in the United States. Secure .gov websites use HTTPS A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites. National Park Service Search Exiting nps.gov Rate the Lesson Plan Field Trips Exploring the C&O Canal's Cushwa Basin Grade Level: Upper Elementary: Third Grade through Fifth Grade Subject: Science,Social Studies State Standards: NATIONAL/STATE STANDARDS:English Language Arts, Speaking and Listening, Comprehension and Co