Colorado, in the Mountain West, is called the “Centennial State,” commemorating its admission to the Union in 1876, 100 years after the signing of the Declaration of Independence. Colorado has about 5.8 million residents. Denver, both the capital and largest city, is known for its proximity to the Rocky Mountains and vibrant cultural scene.
10 Largest Cities in Colorado
1. Denver (Colorado)
City Facts
- County: Denver County (Consolidated City-County)
- Area: 155.4 square miles
- Population: 715,878 (2023 estimate)
- Area Codes: 303, 720
- ZIP Codes: 80201-80299
- Latitude/Longitude: 39.7392° N, 104.9903° W
Location and History
Denver, the capital and largest city of Colorado, is located on the western edge of the High Plains and near the foothills of the Rocky Mountains. Founded in 1858 as a mining town during the Pike’s Peak Gold Rush, it was named after Kansas Territorial Governor James W. Denver. Denver became the territorial capital of Colorado in 1867 and, following statehood in 1876, the state capital. The city’s economy has diversified beyond mining, with industries like aerospace, telecommunications, and energy playing major roles. Denver’s central location makes it a key hub for transportation and commerce in the western United States.
Major Landmarks
- Red Rocks Amphitheatre: A world-renowned outdoor concert venue set in a stunning natural rock formation.
- Denver Art Museum: Features an extensive collection of Native American, contemporary, and classical art.
- Union Station: A historic train station turned hub for dining, shopping, and transit in the heart of downtown.
- Denver Botanic Gardens: A 23-acre garden with plants from around the world, a conservatory, and seasonal events.
- Coors Field: Home to Major League Baseball’s Colorado Rockies, located in the bustling LoDo (Lower Downtown) district.
Major Highways
Denver is a major crossroads for transportation in the region. Interstate 25 runs north-south through the city, connecting Denver to Fort Collins to the north and Colorado Springs to the south. Interstate 70 runs east-west, providing a route to the Rocky Mountains to the west and Kansas to the east. U.S. Highway 36 connects Denver to Boulder, and Interstate 225 acts as a beltway, linking the city to its southeastern suburbs. Interstate 76 runs northeast, providing access to Nebraska.
2. Colorado Springs (Colorado)
City Facts
- County: El Paso County
- Area: 195.7 square miles
- Population: 490,712 (2023 estimate)
- Area Codes: 719
- ZIP Codes: 80901-80951
- Latitude/Longitude: 38.8339° N, 104.8214° W
Location and History
Colorado Springs is located at the base of Pikes Peak in the southern part of the state. Founded in 1871 by General William Jackson Palmer, it was originally intended as a resort destination due to its natural beauty and proximity to the mountains. The city attracted tourists, including gold seekers during the Cripple Creek Gold Rush. Today, Colorado Springs is known for its military presence, including the United States Air Force Academy and several Army installations, as well as its thriving aerospace and defense industries. Its location provides easy access to outdoor recreation and iconic landmarks like Garden of the Gods and Pikes Peak.
Major Landmarks
- Garden of the Gods: A National Natural Landmark featuring dramatic red rock formations and hiking trails.
- Pikes Peak: Known as “America’s Mountain,” it inspired the song “America the Beautiful” and offers a scenic highway and cog railway to the summit.
- United States Air Force Academy: A prestigious military academy with stunning architecture, including the Cadet Chapel.
- Cheyenne Mountain Zoo: The highest zoo in the U.S., known for its giraffe feeding station and scenic views.
- Manitou Springs: A historic town with mineral springs, located just west of Colorado Springs.
Major Highways
Colorado Springs is connected by several major highways. Interstate 25 runs north-south through the city, linking it to Denver to the north and Pueblo to the south. U.S. Highway 24 provides an east-west route through the city, extending west into the mountains and east toward Kansas. State Highway 115 connects Colorado Springs to Fort Carson and Cañon City, while U.S. Highway 85/87 runs parallel to I-25, providing additional connectivity.
3. Aurora (Colorado)
City Facts
- County: Arapahoe, Adams, and Douglas Counties
- Area: 154.7 square miles
- Population: 388,723 (2023 estimate)
- Area Codes: 303, 720
- ZIP Codes: 80010-80047
- Latitude/Longitude: 39.7294° N, 104.8319° W
Location and History
Aurora, located to the east of Denver, was originally founded as the town of Fletcher in 1891, named after developer Donald Fletcher. It was renamed Aurora in 1907 and grew as a suburb of Denver, especially during the post-World War II boom. Aurora is known for its diverse population, excellent healthcare facilities (including the Anschutz Medical Campus), and its strong ties to the military, particularly Buckley Space Force Base. Today, Aurora is one of Colorado’s fastest-growing cities, known for its cultural diversity and outdoor recreation opportunities.
Major Landmarks
- Anschutz Medical Campus: A leading medical and research center, home to the University of Colorado Hospital and Children’s Hospital Colorado.
- Cherry Creek State Park: A large park with a reservoir, hiking trails, camping, and water-based activities.
- Aurora Reservoir: A popular spot for fishing, boating, and picnicking, with scenic views of the Front Range.
- Vintage Theatre: A community theater offering a variety of performances from classic plays to modern productions.
- Aurora History Museum: A museum showcasing the history and culture of Aurora and the surrounding region.
Major Highways
Aurora is served by several key highways. Interstate 225 runs through the heart of the city, connecting it to Interstate 25 in Denver and Interstate 70 to the north. I-70 itself runs east-west, providing a route to Denver International Airport and the mountains. U.S. Highway 285 and State Highway 83 also run through Aurora, providing additional access to surrounding areas. The E-470 tollway, a beltway around the eastern suburbs of Denver, offers quick access to Denver International Airport.
4. Fort Collins (Colorado)
City Facts
- County: Larimer County
- Area: 58.5 square miles
- Population: 174,871 (2023 estimate)
- Area Codes: 970
- ZIP Codes: 80521-80528
- Latitude/Longitude: 40.5853° N, 105.0844° W
Location and History
Fort Collins is located in northern Colorado, along the Cache la Poudre River and at the base of the Rocky Mountains. It was originally founded in 1864 as a military outpost to protect settlers and traders. After the fort was decommissioned, the area became a center for agriculture and education, with Colorado State University (CSU) being established in 1870. Fort Collins has since evolved into a vibrant college town with a focus on technology, research, and outdoor recreation. The city’s historic Old Town area and proximity to Rocky Mountain National Park make it a popular destination for both residents and visitors.
Major Landmarks
- Colorado State University: A leading public research university with a large and active campus in the heart of the city.
- Old Town Fort Collins: A historic district with shops, restaurants, and breweries, known for its charming architecture and vibrant atmosphere.
- Horsetooth Reservoir: A scenic reservoir offering boating, fishing, hiking, and camping just outside the city.
- Fort Collins Museum of Discovery: A museum with interactive exhibits on science, history, and the environment.
- New Belgium Brewing Company: One of the largest craft breweries in the U.S., offering tours and tastings.
Major Highways
Fort Collins is connected to the rest of Colorado by several major highways. Interstate 25 runs north-south through the city, linking Fort Collins to Denver and Cheyenne, Wyoming. U.S. Highway 287 serves as a major route through the city, connecting it to Boulder and Longmont to the south. State Highway 14 provides access to Poudre Canyon and Rocky Mountain National Park to the west. Additionally, local roads provide easy access to neighboring communities like Loveland and Windsor.
5. Lakewood (Colorado)
City Facts
- County: Jefferson County
- Area: 44.0 square miles
- Population: 158,093 (2023 estimate)
- Area Codes: 303, 720
- ZIP Codes: 80214-80235
- Latitude/Longitude: 39.7047° N, 105.0814° W
Location and History
Lakewood, located just west of Denver, was founded in 1889 but remained unincorporated until 1969. Originally a residential community, Lakewood experienced rapid suburban growth during the mid-20th century. The city has since developed into a diverse residential, commercial, and retail center with a mix of urban and natural amenities. Its proximity to the Rocky Mountains makes it an ideal location for outdoor enthusiasts. Lakewood is home to the Federal Center, which houses multiple federal government agencies.
Major Landmarks
- Belmar Shopping District: A vibrant shopping and entertainment area in the heart of Lakewood, with stores, restaurants, and events.
- Lakewood Cultural Center: A community arts center offering theater performances, art exhibits, and workshops.
- Bear Creek Lake Park: A large park with hiking, fishing, and camping opportunities, located at the foot of the Rockies.
- William F. Hayden Green Mountain Park: Offers hiking and biking trails with panoramic views of the Denver metro area.
- Heritage Lakewood Belmar Park: A museum and cultural park preserving the history of Lakewood and the surrounding region.
Major Highways
Lakewood is served by several key highways. U.S. Highway 6 (6th Avenue Freeway) runs east-west through the city, providing a direct route to downtown Denver and Golden. Interstate 70 runs just north of the city, connecting Lakewood to the mountains to the west and Denver to the east. U.S. Highway 285 (Hampden Avenue) runs south from Lakewood, offering access to Littleton and the foothills. Colorado State Highway 470, a beltway, provides easy access to the southern and western suburbs.
6. Thornton (Colorado)
City Facts
- County: Adams and Weld Counties
- Area: 36.9 square miles
- Population: 149,709 (2023 estimate)
- Area Codes: 303, 720
- ZIP Codes: 80229-80602
- Latitude/Longitude: 39.8680° N, 104.9719° W
Location and History
Thornton is located just north of Denver and was incorporated in 1956 as a planned community. It was one of the first communities in the region to offer full municipal services from the outset, which contributed to its rapid growth. Originally a small suburban area, Thornton has grown into a large city known for its family-friendly neighborhoods and parks. The city continues to expand with residential and commercial development, providing a balance between suburban living and easy access to the Denver metropolitan area.
Major Landmarks
- Carpenter Park: A large community park with playgrounds, sports fields, a skate park, and a lake for boating and fishing.
- Thornton Arts and Culture Center: A venue for art exhibits, performances, and community events.
- Trail Winds Recreation Center: A state-of-the-art facility offering fitness programs, swimming, and sports.
- Veterans Memorial Aquatics Center: A premier facility for swimming competitions and community recreation.
- Eastlake Nature Preserve: A scenic park with walking trails, birdwatching, and views of the Front Range.
Major Highways
Thornton is well-connected to the Denver metro area by several highways. Interstate 25 runs through the western part of the city, providing a direct route to Denver and Fort Collins. U.S. Highway 85 runs parallel to I-25, offering an alternative north-south route. State Highway 7 runs east-west through Thornton, connecting the city to Boulder and Brighton. The E-470 tollway runs near the eastern edge of Thornton, offering quick access to Denver International Airport.
7. Arvada (Colorado)
City Facts
- County: Jefferson and Adams Counties
- Area: 39.4 square miles
- Population: 123,436 (2023 estimate)
- Area Codes: 303, 720
- ZIP Codes: 80001-80007
- Latitude/Longitude: 39.8028° N, 105.0875° W
Location and History
Arvada, located northwest of Denver, was founded in 1870 as a small agricultural settlement and grew around the Denver Pacific Railway. The area was known for its rich farmland, and the discovery of gold in nearby Clear Creek helped boost its early economy. Arvada was incorporated as a city in 1904 and gradually transitioned from a farming community to a suburban city. Today, Arvada is known for its historic Olde Town, parks, and easy access to both Denver and the Rocky Mountains. The city offers a mix of suburban living with a vibrant cultural and recreational scene.
Major Landmarks
- Olde Town Arvada: A charming historic district with shops, restaurants, breweries, and cultural events.
- Arvada Center for the Arts and Humanities: A large arts center offering theater performances, art exhibits, and educational programs.
- Two Ponds National Wildlife Refuge: A small urban wildlife refuge with trails and opportunities for birdwatching.
- Majestic View Nature Center: A park with nature trails, educational exhibits, and scenic views of the mountains.
- Ralston Creek Trail: A popular trail for biking and walking, running through several parks in Arvada.
Major Highways
Arvada is connected by several major highways. Interstate 70 runs along the southern border of the city, providing access to Denver and the mountains. U.S. Highway 36 runs just north of Arvada, connecting it to Boulder and Denver. State Highway 121 (Wadsworth Boulevard) runs north-south through the city, serving as a major local thoroughfare. Additionally, local roads connect Arvada to nearby communities like Wheat Ridge and Westminster.
8. Westminster (Colorado)
City Facts
- County: Adams and Jefferson Counties
- Area: 34.1 square miles
- Population: 119,678 (2023 estimate)
- Area Codes: 303, 720
- ZIP Codes: 80003-80234
- Latitude/Longitude: 39.8367° N, 105.0372° W
Location and History
Westminster is located northwest of Denver, between Boulder and Denver. The area was first settled in the 1870s, and the city was incorporated in 1911. Originally a small farming community, Westminster has grown into a suburban city known for its parks, schools, and shopping districts. The city’s development has been shaped by its strategic location between Denver and Boulder, making it a popular residential area for commuters. Westminster’s growth continues with new residential and commercial developments.
Major Landmarks
- Westminster Promenade: An outdoor shopping, dining, and entertainment district with a large movie theater and an ice skating rink.
- Standley Lake Regional Park: A large reservoir offering fishing, boating, camping, and hiking with views of the mountains.
- Butterfly Pavilion: A popular attraction featuring over 1,600 butterflies and other invertebrates in a tropical environment.
- Westminster City Park: A large park with sports fields, playgrounds, and a recreation center.
- Bowles House Museum: A historic house museum showcasing the early history of Westminster and the surrounding area.
Major Highways
Westminster is served by several major highways, making it easily accessible to both Denver and Boulder. U.S. Highway 36 (Boulder Turnpike) runs through the city, connecting Westminster to Denver and Boulder. Interstate 25 is located just east of the city, providing access to northern Colorado and Denver. State Highway 121 (Wadsworth Parkway) runs through Westminster, linking it to nearby Arvada and Broomfield. Additionally, Interstate 76 is accessible to the east, providing connections to the eastern plains.
9. Centennial (Colorado)
City Facts
- County: Arapahoe County
- Area: 29.8 square miles
- Population: 112,623 (2023 estimate)
- Area Codes: 303, 720
- ZIP Codes: 80015-80122
- Latitude/Longitude: 39.5807° N, 104.8772° W
Location and History
Centennial, located south of Denver, is one of Colorado’s newest cities, incorporated in 2001. The city was formed by a vote of residents in several unincorporated areas of Arapahoe County who wanted to control zoning and services for their growing suburban community. Centennial quickly grew into a thriving city with a strong residential base, high-quality schools, and access to major highways and businesses. It has become a popular location for families and professionals working in the Denver Tech Center and other nearby commercial areas.
Major Landmarks
- Centennial Center Park: A large community park with playgrounds, water features, and an amphitheater for concerts and events.
- Cherry Creek State Park: A major recreational area offering camping, fishing, boating, and trails for hiking and biking.
- The Streets at SouthGlenn: A shopping and entertainment district with retail stores, restaurants, and a movie theater.
- Topgolf Centennial: A popular golf entertainment complex offering high-tech driving ranges and dining.
- Arapahoe County Fairgrounds: Hosts the annual Arapahoe County Fair and other community events throughout the year.
Major Highways
Centennial is well-connected to the rest of the Denver metropolitan area by several major highways. Interstate 25 runs along the western edge of the city, providing easy access to downtown Denver and Colorado Springs. Interstate 225 connects Centennial to Aurora and Denver International Airport. E-470, a toll highway, runs through the eastern part of the city, offering quick access to the airport and eastern suburbs. Additionally, local roads like Arapahoe Road and Parker Road (State Highway 83) provide connections to nearby cities like Greenwood Village and Parker.
10. Boulder (Colorado)
City Facts
- County: Boulder County
- Area: 25.8 square miles
- Population: 108,645 (2023 estimate)
- Area Codes: 303, 720
- ZIP Codes: 80301-80310
- Latitude/Longitude: 40.0150° N, 105.2705° W
Location and History
Boulder is located at the base of the Rocky Mountains, about 25 miles northwest of Denver. Founded in 1859 as a supply base for gold miners headed to the mountains, Boulder quickly became an important center for education and culture. The city is home to the University of Colorado Boulder, the state’s largest university, established in 1876. Boulder is known for its progressive culture, outdoor recreation, and environmental focus. It regularly ranks among the top cities in the U.S. for quality of life and outdoor activities, thanks to its proximity to the Flatirons and other natural landmarks.
Major Landmarks
- University of Colorado Boulder: A major public research university with a beautiful campus nestled at the foot of the mountains.
- Pearl Street Mall: A pedestrian-only street in downtown Boulder, lined with shops, restaurants, street performers, and galleries.
- Flatirons: Iconic rock formations just outside Boulder, popular for hiking and rock climbing.
- Chautauqua Park: A historic park offering hiking trails, concerts, and educational programs in a stunning natural setting.
- Boulder Creek Path: A scenic trail that runs along Boulder Creek, offering walking, biking, and access to parks.
Major Highways
Boulder is served by several key highways that connect it to the surrounding areas. U.S. Highway 36 (Boulder Turnpike) runs southeast to Denver, providing the primary route between the two cities. State Highway 93 runs south from Boulder to Golden, offering access to the western suburbs of Denver. State Highway 119 runs north toward Longmont, while State Highway 7 provides a scenic route to Estes Park and Rocky Mountain National Park. Additionally, Boulder’s local roads provide access to the city’s many parks, trails, and natural areas.