When James Monroe and Robert Livingston signed the Louisiana Purchase, they had effectively spent almost twice the money Jefferson had authorized and they hadn't obtained West and East Florida. What they had supposedly obtained was unknown amounts of land West of the Mississippi River (but most, importantly they had gained New Orleans for America). Even France didn't know exact boundaries of the vast land. When Livingston and Monroe asked French Foreign Minister Talleyrand what the boundaries were, he responded, "I can give you no directions. You have made a noble bargain for yourselves and I suppose you will make the most of it." And America did make the most of the purchase; purchasing the Floridas, conquering other countries, and flooding staggering numbers of settlers westward. There were no concrete boundaries before the purchase. "No boundaries" meant less obstacles to American expansion. In fact, the United States had used the Louisiana Purchase as a mandate for mapping out her own boundaries.

The Purchase territory in 1803 actually contains parts of Texas, New Mexico, and Colorado.