Many Colorado towns have "sister cities" that are located in other places across the world. The people-to-people concept was first proposed by President Eisenhower in 1956, which then led to the development of Sister Cities International.

Now, twin towns partner with each other to promote human contact and cultural links. These long-term partnerships are not limited to cities and often include counties, regions, states, and other sub-national entities. Sister cities form close social bonds and interact with each other across a broad range of activities, from health care and education to business and the arts.

A sister city agreement is officially recognized after the highest elected or appointed official from both communities approves and officially signs off on it. There's no limit to how many sister cities a community can have either.

So, who are the sister cities of our Northern Colorado communities?

Fort Collins

Fort Collins has one official sister city - Alcalá de Henares, which is in the community of Madrid, Spain.

Alcalá de Henares has a population of approximately 200,000 residents, making it Spain's third-most populated municipality. Just like Fort Collins, the major landmark and one of the great points of pride of the city is its college university.

The City of Fort Collins also currently has a Friendship City Partnership with San Cristobal de las Casas, Chiapas, Mexico. Like Fort Collins, San Cristobal is particularly interested in water systems, trail development forest protection, and economic development practices. On April 30, 2015, Poudre School District partnered with the City of Fort Collins and CSU to present a Virtual Concert featuring the Bauder Pride Orff Ensemble, Lincoln Middle School Jazz Band, and the San Cristobal de las Casas Marimba Friends of the Sun. The concert was live-streamed between Fort Collins and Mexico. The mayor of Fort Collins, City Officials, and CSU faculty have all visited the Mexican city over the years.

Greeley

Greeley's relationship with its sister city, Moriya, Japan was established in August 1993. Moriya is the smallest city located in Ibaraki Prefecture.

On February 2, 2022, Moriya celebrated its 20th anniversary of becoming a city, a major growth milestone in the Japanese government structure. Like Greeley, its affiliated counterpart in Japan has grown rapidly since the 1970s.

Every odd year summer the City of Greeley sponsors approximately ten high school students to visit Moriya, Japan, as part of a student exchange. During even years, Greeley students host Moriya students.

Longmont

Longmont has three sister cities - Chino, Japan, Ciudad Guzman, Mexico, and the Wind River Reservation in Wyoming.

Longmont's relationship with Chino, Japan dates back to 1990. Many lasting friendships have been built through cultural exchanges between the two municipalities throughout the last 33 years.

In 1997 Ciudad Guzman, Mexico, became Longmont's second sister city. The connection between Longmont and Ciudad Guzman is based on similarities between the two cities and Longmont's large Hispanic population.

Every year, the Longmont Sister Cities Association sponsors an annual student exchange. The exchange brings students from Japan and Mexico to Longmont for a 10-day visit. In turn, students from Longmont participated in a similar 10-day visit to Japan or Mexico.

In 2021, the Northern Arapaho Tribe from the Wind River Reservation in Wyoming became Longmont's third sister city.

Estes Park

Estes Park’s current sister city is Monteverde, Costa Rica. The bond between the two cities was made official in 2004.

Like other sister cities in Colorado, Estes Park and Monteverde have a high school student exchange program. The two towns also facilitate activities and programs that provide appropriate aid, comfort, education, and mutual understanding of culture, environment, and economics to one another.

As of 2023, Berthoud, Loveland, Wellington, and Windsor, Colorado do not have any listed sister cities.