It's the greatest debate of Girl Scout cookie season: are they Samoas or Caramel deLites? Peanut Butter Patties or Tagalongs? The answer depends on where you're from.
Little Brownie Bakers, based in Louisville, Kentucky, makes Samoas, Tagalongs, and Trefoils on both coasts, throughout most of the South, and in most major cities except for Boston and Houston.
ABC Bakers, based in Richmond, Virginia, makes Caramel deLites, Peanut Butter Patties, and Shortbread and sells them in Kansas, Nebraska, Iowa, the Dakotas, Wisconsin, most of North Carolina, and some other areas.
This map from the Los Angeles Times breaks down what cookies are sold where. (Go to their website for a much better interactive version.)
But they're not just different names on cookies sold in the same box — they're actually slightly different cookies, Rosanna Xia and Jon Schleuss report. Thin Mints from ABC are shaped differently and have less chocolate on them than Thin Mints from Little Brownie. Samoas have more toasted coconut than Caramel deLites, and Tagalongs have more peanut butter than Peanut Butter Patties. (There's a great comparison chart on the Los Angeles Times website with pictures of each cookie and more differences between the two bakers' varieties.)
One other secret of Girl Scout cookie naming and production: Little Brownie is a division of Keebler bakeries, owned by Kellogg, and the same factory that produces Girl Scout cookies also produces other, very similar (although not identical) cookies sold year-round under the Keebler brand. It is possible to have Samoas year-round, but when it's not Girl Scout season they're under yet another alias: Keebler Coconut Dreams.
Correction: A previous version of this post misspelled Jon Schleuss's first name.