My highest recommendation goes to:
Stories of Great Americans for Little Americans – Edward Eggleston
Adventures in Colonial America series – James E. Knight
Cheryl Harness (so many great books and well illustrated!)
Benjamin West and His Cat Grimalkin (about the artist)
Some newer ones, expanding the category (hopefully, not overly political, you never know with newer books):
This Is the Rope: A Story from the Great Migration – Jacqueline Woodson
The Other Side – Same as Above
White Socks Only
Russell Freedman (may be too old for his, yet)
David Adler Picture Book series: MLK, Jr.; Helen Keller; Rosa Parks; Harriet Tubman; Jackie Robinson; Frederick Douglass; Amelia Earhart; Sacagawea; Louie Braille, more+
Emma’s Poem: The Story of the Statue of Liberty – Linda Glaser – ages 4-8
Hanukkah at Valley Forge– Stephen Krensky – gr. 2-4
The Yankee at the Seder– Elka Weber – gr. 2-5
As Good as Anybody: Martin L. King and Abraham Joshua Hershel’s Amazing March Toward Freedom– Richard Michelson – ages 6-10