Boulder

Sister cities

• Dushanbe
• Yamagata
• Ramat Negev Regional Council

History

Archaeological evidence shows that Boulder Valley has been continuously inhabited by Native American tribes for over 13,000 years, beginning in the late Pleistocene era. Throughout the Paleo-Indian, Archaic, and Late Prehistoric periods, indigenous peoples moved seasonally between the mountains and plains, taking shelter in winter along the Front Range trough where Boulder now lies. By the 1500s, the Ute people held primary occupation of Boulder Valley. In the early 1800s, the Arapaho migrated to the region. Additional Native American nations with historical ties to the broader Front Range include the Apache, Arapaho, Cheyenne, Comanche, Kiowa, Pawnee, Shoshone, Sioux, and Ute peoples. In the 1800s, European Americans settled in the area. Boulder was founded in late 1858 when prospectors led by Thomas Aikins arrived at Boulder Canyon during the Colorado Gold Rush. According to historical accounts, they initially camped in an area historically associated with Arapaho leader Chief Niwot, though the Arapaho's stable settlement had been displaced by earlier treaty obligations. Under the Treaty of Fort Wise (1861), the Arapaho were formally forced to relocate to the Cheyenne-Arapaho Reservation. Some of these early settlers later participated in the 1864 Sand Creek massacre, where Niwot himself was killed. In early 1859, gold was discovered along Boulder Creek, drawing more miners and merchants to the area. The Boulder City Town Company was formed in February 1859 to establish a settlement at the canyon mouth. The Boulder, Nebraska Territory, post office opened on April 22, 1859. On August 24, 1859, voters of the Pike's Peak mining region approved the formation of the Provisional Government of the Territory of Jefferson, and on November 28, 1859, the extralegal Jefferson…

Geography

The city of Boulder is located in the Boulder Valley, where the Rocky Mountains meet the Great Plains. The Flatirons, slabs of sedimentary stone tilted up on the foothills, are located west of the city and are a widely recognized symbol of Boulder. Boulder Creek is the primary flow of water through Boulder. The creek was named before the city's founding and its etymology is unknown. It is from Boulder Creek that the city is believed to have taken its name. Boulder Creek has significant water flow, derived primarily from snow melt and minor springs west of the city. The creek flows into St. Vrain Creek east of Longmont, which is a tributary of the South Platte River. At the 2020 United States census, the city had a total area of , including of water. Denver International Airport is located east-southeast of Boulder. In 1899, government preservation of open space around Boulder began, with the Congress of the United States approving the allocation of of mountain backdrop and watershed extending from South Boulder Creek to Sunshine Canyon. Boulder has created an Urban Wildlife Management Plan which sets policies for managing and protecting urban wildlife. The city's Parks and Recreation and Open Space and Mountain Parks departments have volunteers who monitor parks, including wetlands, lakes, etc., to protect ecosystems. From time to time, parks and hiking trails are closed to conserve or restore ecosystems. Traditionally, Boulder has avoided using chemical pesticides to control the insect population. However, with the threat of West Nile virus, the city began an integrative plan to control the mosquito population in 2003 that includes chemical pesticides. Residents can opt out of the program by contacting the city and asking that their areas not be sprayed.…

Most-observed species

• House Finch

  Haemorhous mexicanus (P.L.Statius Müller, 1776) · Aves
  58,278
• Black-capped Chickadee

  Poecile atricapillus (Linnaeus, 1766) · Aves
  51,787
• American Robin

  Turdus migratorius Linnaeus, 1766 · Aves
  51,210
• Red-winged Blackbird

  Agelaius phoeniceus (Linnaeus, 1766) · Aves
  48,602
• Northern Flicker

  Colaptes auratus (Linnaeus, 1758) · Aves
  47,726
• Mallard

  Anas platyrhynchos Linnaeus, 1758 · Aves
  45,315
• Canada Goose (canadensis Group)

  Branta canadensis (Linnaeus, 1758) · Aves
  43,640
• Blue Jay

  Cyanocitta cristata (Linnaeus, 1758) · Aves
  43,389

Most recent

• M 2.7 — 2025-06-13
  7 km SE of Erie, Colorado
• M 2.5 — 2020-10-24
  2 km ESE of Georgetown, Colorado
• M 2.9 — 2019-03-30
  7 km NE of Greeley, Colorado
• M 3 — 2016-11-06
  8 km ENE of Greeley, Colorado
• M 2.7 — 2016-11-06
  8 km ENE of Greeley, Colorado
• M 2.6 — 2016-08-23
  2 km SSE of Eaton, Colorado