This is a unit I have used with my 4th grade students. There is a pre and post test to show student growth based on the lessons in this unit. It can be used as is, or modified with 3rd grade up to probably 6th grade. There are many great books to read, a look at the changing geography of the United States in the 20th century, and a baseball biography for students to write.
As the unit ends students will create their own baseball teams, design their uniforms, pennants and stadiums. Then they draft real Major Leaguers and play Fantasy Baseball.