Children's Encyclopedia of American History is a valuable resource. The more I reference or read it, the more I like it. 
 Even if we weren't homeschooling, I would want to own this book to supplement learning American history. Primary source illustrations and brief text provide an engaging overview. Maps and photographs are typical of the format and publisher, but what I particularly liked are the primary source illustrations. Artwork, hand bills, line drawings (one by John Smith, one by Daniel Boone in early chapters), models of ships and photographs of traditional housing provide not only data, but a visual feel for a time period. The text ends with the September 11th attacks. 
 Although somewhat biased in places (there is a somewhat disproportionate mention of women and the environment), overall the text captures important people and events with brevity and works impressively to avoid partisanship. The occasional paragraph doesn't ring true, but overall this is a solid work, and you will be hard pressed to find much better (unless a biased work completely in favor of your opinions is what you are seeking). 
 Appendices continue the pattern of excellence in presentation combined with commitment to primary sources. Presidents of the United States, Facts about the USA, and a state by state chart are followed by The Declaration of Independence and the Constitution (including the Bill of Rights) and the Gettyburg Address. 
 Highly recommended for students of all ages seeking to understand the timeline of American history.