Why does Oklahoma have that panhandle? Did someone make a mistake? We are so familiar with the map of the United States that our state borders seem as much a part of nature as mountains and rivers. Even the oddities—the entire state of Maryland(!)—have become so ingrained that our map might as well be a giant jigsaw puzzle designed by Divine Providence. But that's where the real mystery begins.

Every edge of the familiar wooden jigsaw pieces of our childhood represents a revealing moment of history and of, well, humans drawing lines in the sand. How the States Got Their Shapes is the first book to tackle why our state lines are where they are. Here are the stories behind the stories, right down to the tiny northward jog at the eastern end of Tennessee and the teeny-tiny (and little known) parts of Delaware that are not attached to Delaware but to New Jersey.

How the States Got Their Shapes examines:

• Why West Virginia has a finger creeping up the side of Pennsylvania
• Why Michigan has an upper peninsula that isn't attached to Michigan
• Why some Hawaiian islands are not Hawaii
• Why Texas and California are so outsized, especially when so many Midwestern states are nearly identical in size

Packed with fun oddities and trivia, this entertaining guide also reveals the major fault lines of American history, from ideological intrigues and religious intolerance to major territorial acquisitions. Adding the fresh lens of local geographic disputes, military skirmishes, and land grabs, Mark Stein shows how the seemingly haphazard puzzle pieces of our nation fit together perfectly.