Why are Alaska, California and Texas so much larger than the other states? Why are the states in the Northeast so small? What is that panhandle in Oklahoma about? These questions and many more are answered in "How the States Got Their Shapes" by Mark Stein. The tone is lighthearted but factual, and it makes for a great grab-off-the-shelf-and-read-a-few-chapters addition to any geographer’s bookshelf.
The book starts with a section titled, "Don't Skip This!" and I agree. This chapter lays down the foundation for what is to follow, which is 51 chapters on each of the 50 states and the District of Columbia. Since all of the state boundaries overlap (obviously), "Don't Skip This!" provides the broader context of how these boundaries came to be.
The states are listed alphabetically, from Alabama to Wyoming, and each state starts with a set of questions like the ones above. The text is written for an informed and curious lay reader, and includes descriptions of latitude, longitude, water bodies and other geographic features. Each state chapter offers several maps, each annotated to the text description.
Now, in answer to the questions posed above... Alaska was a good deal, at $0.02 an acre and created sovereign borders to keep out the Russians and British. Although called Seward’s Folly at the time, it has obviously paid off well with the state’s richness in crude oil, fisheries, tourism and timber.
The U.S. needed California — and fast! — after gold was discovered. There were British in the north, Russians on the coast, and Mexicans in the south. It was populous and prosperous enough that it didn’t have to go through the territory process; it immediately became a state.
The same is true of Texas. It was a Mexican state, then an independent republic, and with conflict imminent, was quickly annexed as a state using pre-defined borders.
For answers to the other questions, you’ll just have to read the book!