Longmont 155 | Colorado 150 | United States 250 - City of Longmont

Longmont 155 | Colorado 150 | United States 250

One plat map of the Chicago-Colorado Colony, green background. Titled at top "Longmont. Chicago Colorado Colony" and "Organized at Chicago No. 22, 1870. Map shows the first block of the original square mile of Longmont,

Celebrating 155 years of Longmont 

 

Did you know 2026 marks not one, not two, but three significant anniversaries?

In 2026, Longmont turns 155, Colorado will celebrate 150 years of Statehood, and the United States will mark 250 years since the signing of the Declaration of Independence. These triplet milestones are a rare and exciting opportunity to unite with our community in celebration of our past and to imagine our future together.

 

In Longmont, we will mark these anniversaries by exploring the history of our city and by hosting commemorative events and activities.

 

Check out the Celebrations Calendar below, invite your friends and family to join in the fun, and follow along as we journey through history and celebrate together!

 

Celebrations Calendar

Voices of Change: A Civics Lesson
Voices of Change: A Civics Lesson
Thursday, Feb. 26 • 7 pm - 9 pm
400 Quail Rd. Longmont, CO 80501 United States
Talk with the Curator: The History of Celebrating Anniversaries in Longmont
Talk with the Curator: The History of Celebrating Anniversaries in Longmont
Friday, Feb. 27 • 2:30 pm - 4 pm
400 Quail Rd. Longmont, CO 80501 United States
Museum
Behind the Scenes Tour of the Museum Collections Center
Behind the Scenes Tour of the Museum Collections Center
Tuesday, Mar. 10 • 10:30 am - 12 pm
400 Quail Rd. Longmont, CO 80501 United States
Museum
Behind the Scenes Tour of the Museum Collections Center
Behind the Scenes Tour of the Museum Collections Center
Tuesday, Mar. 10 • 5:30 pm - 7 pm
400 Quail Rd. Longmont, CO 80501 United States
Museum
The Birth of American Classical Music: Dvořák, Gershwin & Copland
The Birth of American Classical Music: Dvořák, Gershwin & Copland
Thursday, Mar. 12 • 7 pm - 9 pm
400 Quail Rd. Longmont, CO 80501 United States
Museum
Talk with the Curator: Longmont’s Founding
Talk with the Curator: Longmont’s Founding
Friday, Mar. 27 • 2:30 pm - 4 pm
400 Quail Rd. Longmont, CO 80501 United States
Museum
Mont Alto Motion Picture Orchestra: The General (1926)
Mont Alto Motion Picture Orchestra: The General (1926)
Thursday, Apr. 2 • 7 pm - 9 pm
400 Quail Rd. Longmont, CO 80501 United States
Museum
Life, Liberty & The Pursuit of a Narrative
Life, Liberty & The Pursuit of a Narrative
Thursday, Apr. 9 • 7 pm - 9 pm
400 Quail Rd. Longmont, CO 80501 United States
Museum
Talk with the Curator: Grandma’s Recipe Box Potluck
Talk with the Curator: Grandma’s Recipe Box Potluck
Friday, Apr. 24 • 2:30 pm - 4 pm
400 Quail Rd. Longmont, CO 80501 United States
Museum
Talk: Utopian Colorado
Talk: Utopian Colorado
Thursday, Apr. 30 • 7 pm - 9 pm
400 Quail Rd. Longmont, CO 80501 United States
Museum
View Events

Explore More History with Longmont’s Virtual Tours 

Women of Longmont Virtual Tour

Discover the lives of influential women who helped make Longmont the vibrant, community-focused town it is today.

Historic Downtown Virtual Tour

Enjoy historic photographs, text, and audio recordings that virtually walk you through more than a dozen downtown locations.

Latino History Virtual Tour

This tour explores Longmont’s Latino neighborhoods and heritage while honoring some of the many sacrifices, challenges and successes experienced by this remarkable community.

In the Spotlight:

Photos of Influential Women in Longmont’s History 

 

  • Color picture postcard depicting at least sixteen or more women on horseback. The women are wearing brimmed hats, some with white blouses and ties, others with colored long sleeve blouses and riding pants. At the bottom of the postcard printed on a white border is "Ladies Riding Club, Longmont, Colo"
  • Photograph of 19 young women in 1908 wearing white blouses and dark skirts standing, kneeling, and sitting in three rows.
  • Black and white photo of a woman sitting on a chair in the middle of the lawn under a blanket while a band of men serenade her with their brass band.
  • Smiling woman sitting on the front tire of a tractor
  • Black and white snapshot of three women standing beside a biplane with the male pilot in the cockpit. The woman on the left is wearing a canvas aviator's cap with goggles perched on top of her head.

Is Sesquisemiquincentennial a real word?

Sesquisemiquincentennial badgeIt sure is! You may see “Sesquisemiquincentennial” used around the state of Colorado this year. In 2026, Colorado celebrates its 150th anniversary of statehood (sesquicentennial) and the United State’s 250th anniversary (semiquincentennial) since the signing of the Declaration of Independence. Learn about more celebrations around the state on the History Colorado website.

 

Sesquicentennial + Semiquincentennial = Sesquisemiquincentennial

 

The City of Longmont, in collaboration with the American 250-Colorado 150 Commission, celebrates this unique anniversary year by looking back at Longmont’s 155 years of history. Follow this webpage to learn more about how you can celebrate with us, in person and online!

Severe Weather Shelter Information: Feb. 18-21, 2026

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