Related by context. Frequent words. (Click for all words.) 51 Donner Pass 50 Ernest Shackleton 49 Chaco Canyon 49 aviator Amelia Earhart 48 Meriwether Lewis 47 Mormon pioneers 47 Pony Express 46 Sierra Nevadas 46 Abominable Snowman 46 cliff dwellings 46 Fort Clatsop 46 Clark Expedition 46 Paiutes 46 woolly mammoths 46 Transcontinental Railroad 46 Gold Rush 45 Petrified Forest 45 Salem Witch Trials 45 Lassen Volcanic National 45 backcountry 45 Spanish conquistadors 45 cannibalism 45 Yosemite Valley 45 Alder Creek 45 Sir Ernest Shackleton 44 Dust Bowl 44 Irish potato famine 44 Barrens 44 Bataan Death March 44 Southern Appalachians 43 Comstock Lode 43 pronghorns 43 Lolo Pass 43 Continental Divide 43 Manzanar 43 alpinists 43 expedition 43 Ferdinand Magellan 43 Canyon de Chelly 43 backcountry ski 43 Hells Canyon 43 Native Americans 43 fugitive slaves 43 Twain 42 Zodiac killer 42 Sierras 42 stagecoaches 42 Donner 42 snowfield 42 James Fenimore Cooper 42 Mothman 42 Lost Dutchman 42 rugged wilderness 42 Little Bighorn 42 spelunkers 42 Great Famine 42 Rim Trail 42 Mono Lake 42 Grizzly bear 42 Nanga Parbat 42 sled dogs 42 sasquatch 42 pictographs 42 Zane Grey 42 Machu Picchu 42 Roald Amundsen 41 prehistory 41 Ken Kesey 41 couloir 41 Wagon Train 41 Mammoth Cave 41 hauntings 41 Santa Ana Mountains 41 yeti 41 backcountry skiers 41 Wawona 41 Johnstown Flood 41 ancestors 41 explorers 41 Timothy Treadwell 41 Whiskeytown 41 mastodons 41 backpacking trips 41 wilderness 41 Trinity Alps 41 Dian Fossey 41 Appalachian Mountains 41 ancient Mayans 41 Noah Ark. 41 Arctic explorer 41 adventurers 40 Civil War 40 Mount Katahdin 40 potato famine 40 voyageurs 40 icefall 40 Furthur 40 Kesey 40 grizzly bears 40 canyon 40 Anasazi