Longmont is a home rule municipality located in Boulder and Weld counties, Colorado, United States.

The city began to flourish as an agricultural community after the Colorado Central Railroad line arrived northward from Boulder in 1877.

In 1925, the Ku Klux Klan gained control of Longmont's City Council in an election.

They began construction of a large pork-barrel project, Chimney Rock Dam, above Lyons and marched up and down Main Street in their costumes.

Work on Chimney Rock Dam was abandoned as unfeasible, and its foundations are still visible in the St. Vrain River.

[11][12] In 1955, United Airlines Flight 629 exploded over Weld County, Colorado 8 miles east of Longmont, killing 44 passengers and crew.

In 1950 they constructed a large plant on southern Main St. that received trucks full of live turkeys.

During the mid-1990s, the southern edge of Longmont became the location of the first New Urbanist project in Colorado, called Prospect New Town, designed by the architects Andrés Duany and Elizabeth Plater-Zyberk.

Longmont was the site of Colorado's first library, founded in 1871 by Elizabeth Rowell Thompson, though it lasted up to a year before its collection of 300 books was lost.

[15] In May 2013, the Longmont City Council voted to finance and build out its own municipal gigabit data fiber-optic network, known as NextLight, to every house and business over a three-year period starting in late 2013.

That year the library's director stated, in the words of Corey Hutchins of the Columbia Journalism Review, "lacks resources and hasn’t kept up with the city’s growth".

[26] Longmont has bus service to Denver and Boulder as part of the RTD transit district.

Longmont is connected to Fort Collins, Loveland, and Berthoud via a FLEX regional bus service.

As of 2024[update], the FasTracks project plans to extend RTD's commuter rail B Line to Longmont, which could be completed in the early 2040s.

Sports radio is broadcast on KKSE-FM from a tower about 10 miles (16 km) southeast of Longmont.

Also located nearby is KDFD, a Fox News Radio affiliate with a conservative talk format.

NPR programming can be heard on Colorado Public Radio stations KCFR from Denver, and KCFC (AM) in Boulder.

Local breweries include two of the nation's largest craft brewers,[32] Left Hand and Oskar Blues, as well as many others.

[45][44] At the federal level, Longmont is a part of Colorado's 2nd congressional district, which is currently represented in the United States House of Represenatives by Congressman Joe Neguse (D).