Part of the Western United States, the Southwestern United States, and the Mountain States, Colorado is the 38th state to join the Union (on August 1, 1876) and with a population of 5,348,476 is today the 22nd most populous state. Colorado is known as the The Centennial State
State Abbreviation: CO Capital City: Denver Largest City: Denver Number of Counties: 64 Area: 104,094 square miles Major Rivers:Colorado River, Rio Grande, Animas River and Arkansas River Major Lakes: Grand Lake, Blue Mesa Reservoir, John Martin Reservoir Highest Point: Mt. Elbert; 14,433 feet feet above sea level State Motto: "Nil sine Numine" - Nothing Without Providence State Bird: Lark bunting State Insect: Hairstreak Butterfly State Fish: Greenback Cutthroat Trout State Amphibian:Western tiger salamander State Tree: Blue Spruce State Flower: Rocky Mountain Columbine (White and Lavender) State Gemstone: Aquamarine