Geography is one area of social studies. Colleges are often specific about what they want to see for high school social studies, including American history, world history, economics, and American government. Since economics and government are often just half-year classes, together they take only one year.
This leaves you with some options - with three years of social studies specified, one year of social studies can be more delight directed. Options include geography, psychology, sociology, anthropology, and other "ologies" as well.
I am often asked to give suggestions for geography programs. But geography can simply be taught within the context of other social studies classes. In other words, world history may include some of the geography of Europe.
If you do want to teach separate history and geography classes, we loved Runkle's The Wonderful World of Geography. It's worth it to pick up the student activity workbook as well.
If you want to cover physical geography, this curriculum is great! It is designed for grades 6 through high school. If your child is high school age, I would include it on the high school transcript. My children memorized all the countries of the world using this curriculum. We loved it and still use the information regularly!