Yosemite Triple Decal - YOSE

Where does this abbreviation come from? The National Park Service assigns each unit it manages (National Parks, National Monuments, National Historic Sites, etc.) a unique abbreviation code to help standardize communications both internally and externally (i.e. web addresses). But due to the large number of units involved, something as simple as the first letter of the site's name, followed by NP, for example,. would not work because multiple parks start with the same letter. 

Can you figure out the basic pattern they ended up using (with some exceptions to the rule)?

1. A four-letter combination
2. If a unit consists of only one word, then it's assigned the first four letters of that word (e.g., REDWOOD National Park = REDW).
3. If the unit name consists of two or more words, it's assigned the first two letters of the first two words (e.g., CRATER LAKE National Park = CRLA).

You can become a National Park System insider by learning and using these abbreviations. To practice your detective skills, see how many exceptions to the rule you can find!

smaller stickers - 2.5 x 1.5 inches

large sticker - 5.5 x 3 inch