Kindergarten: focus on self, family, immediate community, rules & relationships

1st grade: focus on society & self, community helpers, maps, time, cultural traditions

2nd grade: focus on contributing to society, roles of citizens, regions, simple economic systems, language & beliefs

3rd grade: focus on economics on state / community level, regions, land use, resources, environment

4th grade: focus on state / local history, major events, government and civic ideas, Constitution

5th grade: focus on early U.S. history, colonization, revolution, how governments are formed, cultural diversity

6th grade: focus on world / regional studies and geography, continents, major civilizations, humans & their environment

7th grade: State History (usually taught in 7th or 8th)

8th grade: U.S. History (Constitution & Early Republic)

9th grade: Geography

10th grade: World History

11th grade: U.S. History (Reconstruction > Present Day)

12th grade: Government & Personal Finance / Economics

States mostly agree on what needs to be taken for graduation, though they may vary on which grade students traditionally take a particular social studies subject. Many states introduce U.S. history content in elementary school and middle school, and then dedicate a full-year to it in high school, but the grades vary on when this is done depending on what state you're in. 28 states require an economics course and 35 require a 'personal finance' course. The list above is definitely not exhaustive, but it should give you a good idea of what topics are covered around which grades and how they build on each other.