Little House in the Big Woods by Laura Ingalls Wilder. So I have a boy, but we're still going to read the whole series. Fabulous descriptions of life on the American frontier and amazing detail on how things were done in "the old days" from harvesting and processing maple syrup to building log cabins to weaving straw hats. Perfect book for any age.
Also on these boards
Farmer Boy, by Laura Ingalls Wilder.
By the Shores of Silver Lake by Laura Ingalls Wilder