Boulder, Colorado

**Boulder** is a city in the state of Colorado, in the United States. It is the county seat of Boulder County. Boulder is in the foothills of the Rocky Mountains. The city's height is . It is  northwest of Denver. In 2020, there were 108,250 people living the City of Boulder. The Boulder Metropolitan Statistical Area has 330,758 people living in it.

Boulder is famous for its history and its Western traditions. In the late 1960s, lots of hippies moved to Boulder. The main campus of the University of Colorado, the University of Colorado at Boulder, is also here. CU Boulder is the biggest university in Colorado.

## History

On November 7, 1861, the government decided to build a university in Boulder. The legislature decided that the university would be run by the state. The first building was built in 1875. The cornerstone for the Old Main Building was laid on September 20, 1875. The university was officially opened on September 5, 1877.

In 1907, the city of Boulder passed an anti-saloon ordinance. This law said that saloons and bars could not do business in the city, and that people could not drink alcohol. In 1916, the entire state of Colorado started prohibition. In US History, the "Prohibition Era" was a time when all alcohol was illegal. People could not make, drink, buy, sell, or serve alcohol. Prohibition ended in 1933, when the Twenty-first Amendment to the United States Constitution was passed by Congress.

## Demographics

The 2020 United States Census said there are 108,250 people living in the City of Boulder. These people make up 43,565 households. The population density was 4,111.7 people per square mile (1,587.5 people/km²). According to the census, the people living in Boulder are 78.8% White, 1.3% black or African-American, 0.6% Native American, 6.4% Asian, 0.1% Pacific Islander, 4.7% of another race, and 8.1% of two or more races. 10.6% of the population are Hispanic or Latino of any race.

## Geography

Boulder is in Boulder Valley. This is a place where the Rocky Mountains meet the Great Plains. To the West of the city are some rock formations called the Flatirons. These are large flat pieces of stone that are tilted up on the foothills. The Flatirons are famous as a symbol of Boulder.

Boulder Creek flows through the City. Boulder Creek was named a long time before the city was built. It was named after the big granite boulders that have fallen into the creek over the years. Historians think that Boulder was named after Boulder Creek. The water in Boulder Creek comes from melting mountain snow and small rivers West of the city. Boulder Creek is a tributary of the South Platte River.

Boulder covers  according to the U.S. Census Bureau. This includes  of land and  (3.8%) of water.

The 40th parallel (40 degrees north latitude) runs through Boulder. Baseline Road runs along the parallel today.

Flagstaff Mountain overlooks Boulder. The city is a few miles east of the Continental Divide and about  northwest of Denver. Denver International Airport is about  southeast of Boulder. The city gets its water from Arapahoe Glacier and Boulder Creek.

### Climate

Boulder has a dry climate. It has many sunny or mostly sunny days every year. According to the Köppen climate classification, the city's climate is "semi-arid" (Köppen _BSk_). Winters are cool, but sometimes can get very cold. During the winter, the high temperature is usually in the mid- to upper- 40s°F (7–9 °C). The low temperature in winter can be below −10 °F (−23 °C) on a few nights. Usually it does not stay below 0 °F (−18 °C) for many days at a time.

Even though it is cold in the winter, Boulder does not get as much snow as the mountains. This is because of something called orographic lift. This means that the mountains in the west dry out the air as it passes over the Front Range. By the time the air gets to Boulder, most of the water and snow has been removed. Sometimes there are heavy snow storms, but not too often. The average amount of snow in Boulder is  per season, total. Usually only a few inches fall at a time. Because Boulder is so high up, the sun is very strong and hot, so the snow melts quickly. Sometimes Chinook Winds will make the temperature go up quickly and have the snow melt even faster.

Summer in Boulder is hot and dry. Usually there are 27 days during the summer that reach  or above. It is much cooler at night because of how high up the city is. The hottest temperature ever was on June 23, 1954 and July 11, 1954. On those days it was . The coldest temperature was in February 1989 and December 1990, when it was .

## Politics and government

Boulder is a Home Rule Municipality. In Colorado, this means that Boulder's government was formed according to three different legal documents. These documents are: Article XX of the Constitution of the State of Colorado; Title 31, Article 1, Section 202 of the Colorado Revised Statutes; and Boulder's own Home Rule Charter.

Boulder is very liberal and very Democratic. , registered voters in Boulder County were 41% Democrat, 20% Republican, 1% other parties, and 38% unaffiliated (not any specific party.) Boulder County includes the conservative suburbs of Boulder.

Boulder was the first city in Colorado to pass a law that made it illegal to discriminate against people because of their sexual orientation. This law was passed by the Boulder City Council in 1974. The law was repealed (cancelled) by the voters that same year. In 1975, Boulder became the second city to ever grant a same-sex marriage license. The license was given by Boulder County Clerk Clela Rorex. Soon after a law was passed that said that marriage licenses could not be given to people of the same gender. In 1987, the people of Boulder voted again to make it illegal to discriminate against people because of their sexual orientation. This was passed by popular vote. Boulder became the first city in the United States that had this kind of a law that was passed by a direct vote of the people.

## Sister cities

Boulder has seven official sister cities:
- Dushanbe, Tajikistan (May 8, 1987)
- Jalapa, Nueva Segovia Department, Nicaragua (1983)
- Kathmandu, Nepal (2018)
- Kisumu, Kenya (2008)
- Lhasa, Tibet, China (1986)
- Ciudad Mante, Mexico (2000)
- Nablus, West Bank, Palestine (2016)
- Ramat HaNegev, Southern District, Israel (2018)
- Yamagata, Japan (1994)
- Yateras, Guantánamo Province, Cuba (2002)

There are several landmarks in Boulder in honor of the sister cities. The Sister City Plaza was dedicated in May 17, 2007. It is on the east lawn of Boulder's Municipal Building. The plaza was built in honor of Boulder's relationships with its sister cities.

## Infobox (settlement)

- **name**: Boulder, Colorado
- **official name**: City of Boulder, Colorado
- **settlement type**: :en:List of municipalities in Colorado#Home rule municipality, Home rule city
- **image skyline**: Pearl Street Mall.jpg
- **image caption**: :en:Pearl Street Mall, Pearl Street Mall in downtown Boulder, Colorado.
- **image map**: File:Boulder County Colorado Incorporated and Unincorporated areas Boulder Highlighted 0807850.svg
- **map caption**: Location of the City of Boulder in
- **pushpin map**: USA
- **pushpin label**: Boulder
- **pushpin label position**: right
- **pushpin map caption**: Location of the City of Boulder in the
- **subdivision type**: List of sovereign states, Country
- **subdivision type1**: U.S. state, State
- **subdivision type2**: List of counties in Colorado, County
- **subdivision name2**: Boulder County, Colorado, Boulder County seat
- **established title**: Settled
- **established date**: 1858 as Boulder City, Nebraska Territory, N.T.
- **established title2**: Municipal corporation, Incorporated
- **established date2**: 1871-11-04
- **government type**: Colorado municipalities#Home rule municipality, Home rule municipality
- **leader title**: Mayor
- **leader name**: Aaron Brockett (Democratic Party (U.S.), D)
- **leader title1**: Mayor Pro Tem
- **leader name1**: Lauren Folkerts
- **unit pref**: US
- **total type**: Total
- **area total km2**: 70.877
- **area land km2**: 68.188
- **area water km2**: 2.689
- **elevation m**: 1621
- **population as of**: 2020 United States census, 2020
- **population total**: 108,250
- **population rank**: List of municipalities in Colorado, 12th in Colorado
List of United States cities by population, 289th in United States
- **population density sq mi**: 4,112
- **population demonym**: Boulderite
- **population metro**: 330,758 (List of metropolitan statistical areas, 155th)
- **population blank1 title**: Denver-Aurora, CO Combined Statistical Area, CSA
- **population blank1**: 3,623,560 (List of primary statistical areas, 17th)
- **population blank2 title**: Front Range Urban Corridor, Front Range
- **population blank2**: 5,055,344
- **timezone1**: Mountain Time Zone, MST
- **utc offset1**: −07:00
- **timezone1 dst**: Mountain Time Zone, MDT
- **utc offset1 dst**: −06:00
- **postal code type**: ZIP Codes
- **postal code**: 80301-80310, 80314, 80321-80323, 80328, 80329
- **area code**: Both Area code 303, 303 and Area code 720, 720
- **blank name**: Federal Information Processing Standards, FIPS code
- **blank info**: 08-07850
- **blank1 name**: Geographic Names Information System, GNIS feature ID
- **blank1 info**: 178680
- **blank2 name**: state highways in Colorado, Highways
- **blank2 info**: