When my children were little, I had a lot of those wooden puzzles that came in their own wooden board. One of these was a map of these United States, with just the state and its capital (with a star) on it. My kids all knew all of their states and capitals by Kindergarten!
Little kids adore knowing about "stuff," more than loving to be able to read and write and do maths. That is why my First Grade teacher daughter and I cooked up the idea that she would begin to teach Geography and I would write the book. So she did, and I did. Now there are half a dozen teachers teaching it and this is Becky's FIFTH YEAR of teaching it. It has been wildly successful, her kids excel in vocabulary and reading, the parents and grandparents are hugely enthusiastic, and best of all, because it is not a required subject, Becky does not test them in it. Just once she did, for two reasons. It was in the spring of her first year of teaching it, and she wanted to know how they were doing. So she arranged to test just her First Graders against all 4 of the Fifth Grade classes. Her First Graders beat the Fifth Graders all to bits! She used the results in putting in for a grant, which she won. I am working on a Second Grade and Third Grade Geography curriculum, as well.
Those little kids are really amazing in what they are interested in and what they retain. Most of all, especially the boys, they love learning the flags. They do 36 countries in each year. That is, 36 each for First, Second and Third Grade. They study one country per week, and always have a Show & Tell about what they have researched. Lots of parents and grandparents come in to tell of their travels; for some it may even be a native country. They bring in lots of stuff to show and, best of all, to eat.