The earliest known pumpkin pie recipe actually came from Europe in the17th century. Pumpkins, like potatoes and tomatoes, were first introduced to Europe on the Columbia Exchange, but Europeans prefer to cook with pumpkins because they are similar to their native gourds.
However, by the18th century, Europeans generally lost interest in pumpkin pie. According to HowStuffWorks, Europeans began to prefer apples, pears and papaya pies, which they thought were more exquisite. But just as pumpkin pie fell out of favor in Europe, it gained a real staple food status in the United States.
1796, Amelia Simmons published "American Cooking", which was the first cookbook written and published in a New World colony. Simmons offers two recipes for making fluffy pudding with pastry. Simmons' recipe calls for the use of "stewed and filtered" pumpkins, mixed with nutmeg, allspice powder and ginger (yes, our obsession with pumpkin spices seems to date back at least to AD 1500).
But what does pumpkin pie have to do with Thanksgiving? This is related to Sarah Josepha Hale, a writer and editor born in New Hampshire, who is often called "the godmother of Thanksgiving". Hale described a Thanksgiving dinner in her abolitionist novel Northwood (1827), which included "fried chicken floating in gravy", roasted ham, wheat bread, cranberry sauce and, of course, pumpkin pie. For more than 30 years, Hale has advocated making Thanksgiving a national holiday, writing editorials regularly and writing letters to five American presidents. She believes that Thanksgiving Day is a symbol of unity in an increasingly divided country [PDF].
Abraham lincoln finally declared Thanksgiving as a national holiday in 1863 (which almost immediately aroused strong feelings of southerners, who thought it was to strengthen Yankee values). The governor of the south reluctantly obeyed the president's announcement, but the chefs in the south developed their own unique regional traditions. In the south, sweet potato pie soon became more popular than pumpkin pie in New England (mainly because sweet potatoes are easier to buy than pumpkins). Today, pumpkin pie has become the most popular holiday pie in most parts of the United States, although the northeast prefers apples, while the south is divided into apples and pecans, which are another staple food in the south.