Adams County, located in northeastern Colorado, is a region with a rich history dating back to the late 1800s, shaped by westward expansion, agricultural development, and the growth of transportation networks. Established in 1902 and named after Alva Adams, a three-time governor of Colorado, the county has transformed from a primarily agricultural area to one of the most populous and economically diverse counties in the state. Its early growth was driven by the arrival of railroads, which connected local communities to Denver and beyond. Today, Adams County is known for its historical sites, diverse population, and vibrant cultural landscape, blending historic preservation with modern growth.
Origins of Adams County
Early Settlement and Agricultural Beginnings
Adams County was originally part of Arapahoe County before it was officially established in 1902. The region’s history of settlement began in the mid-1800s when gold was discovered in the nearby South Platte River, drawing settlers to the area. However, Adams County’s primary appeal was not gold but agriculture. The area’s fertile soil and proximity to the South Platte River made it ideal for farming, and settlers quickly established homesteads. By the 1870s, wheat, corn, and sugar beets became staple crops in the region.
The construction of railroads in the late 19th century facilitated the transport of agricultural goods, transforming the local economy and encouraging population growth. The Denver Pacific Railway and Union Pacific Railroad, which ran through the county, played an instrumental role in its development, connecting farmers to Denver and other markets throughout Colorado and the Midwest.
Establishment of the County (1902)
Adams County was officially formed in 1902, carved from portions of Arapahoe County. It was named after Alva Adams, Colorado’s governor at the time, in recognition of his contributions to the state’s development. The county’s boundaries were later adjusted, with Denver annexing portions of the county in 1903. Brighton, located on the northern edge of the county, became the county seat, providing a central hub for governance and commerce.
Key Historical Events in Adams County
Adams County’s history has been shaped by several key events, including the development of agriculture, the construction of military and aviation facilities, and major transportation projects that have bolstered its economy and population growth.
Agricultural Boom and Sugar Beet Industry
In the early 1900s, sugar beets became one of Adams County’s most important crops due to high demand. Sugar beet processing factories were established, including one of the largest factories in Brighton. These factories became a primary source of employment for local residents, and the sugar beet industry supported the county’s economy well into the 20th century. Immigrant workers, particularly from Mexico, contributed significantly to the labor force, adding to the area’s cultural diversity.
World War II and the Rocky Mountain Arsenal
During World War II, the U.S. government established the Rocky Mountain Arsenal in Adams County. Originally built as a chemical weapons manufacturing facility, the Arsenal produced mustard gas, lewisite, and other chemical weapons. Following the war, it was repurposed for pesticide production. Over time, the Arsenal’s environmental impact became a concern, leading to extensive cleanup and environmental restoration efforts in the late 20th century. Today, the Rocky Mountain Arsenal National Wildlife Refuge occupies the area, serving as a protected habitat for diverse wildlife and offering recreational opportunities for residents and visitors.
Growth of Aviation: Denver International Airport (1995)
In 1995, Denver International Airport (DIA) was constructed on the eastern edge of Adams County, significantly impacting the region’s economy. As one of the largest airports in the United States, DIA brought substantial economic growth to Adams County, attracting businesses, hotels, and other services that catered to travelers and airport staff. The airport also spurred residential development in nearby communities, contributing to the rapid population growth seen in Adams County over the past few decades.
Historical Sites in Adams County
Adams County is home to several historical sites that reflect its diverse history, from agricultural landmarks to military facilities repurposed for public use. These sites allow visitors to explore the county’s historical evolution and connect with its past.
Rocky Mountain Arsenal National Wildlife Refuge
Overview
The Rocky Mountain Arsenal National Wildlife Refuge is one of the most significant historical and ecological sites in Adams County. Once a chemical weapons manufacturing facility during World War II, the Arsenal underwent one of the most extensive environmental cleanup efforts in U.S. history and was converted into a wildlife refuge. Today, the refuge spans over 15,000 acres and provides a protected habitat for bison, deer, bald eagles, and other wildlife. Visitors can explore hiking trails, participate in wildlife viewing, and learn about the Arsenal’s history at the visitor center.
Location
6550 Gateway Road, Commerce City, Colorado.
Ticket Price
Admission is free.
Parking Information
Free parking is available at the visitor center and other designated areas throughout the refuge.
Adams County Historical Museum
Overview
The Adams County Historical Museum, located in Brighton, offers exhibits on the county’s agricultural heritage, early settlers, and cultural history. The museum showcases artifacts from the county’s early farming communities, including tools, photographs, and household items. It also provides educational programs and events that celebrate the region’s history, from Native American artifacts to 20th-century memorabilia.
Location
9601 Henderson Road, Brighton, Colorado.
Ticket Price
Admission is free, though donations are encouraged.
Parking Information
Free on-site parking is available for visitors.
Bromley-Koizuma-Hishinuma Farm
Overview
The Bromley-Koizuma-Hishinuma Farm is a historic site reflecting the multicultural heritage of Adams County’s agricultural community. Built in the 1880s, the farm was initially owned by German immigrants but was later managed by Japanese-American farmers. The site provides a unique perspective on the challenges and contributions of Japanese-American farmers, particularly during World War II, when many faced internment. Today, the farm is preserved as a historical site, featuring guided tours that provide insight into the lives of early farmers in Adams County.
Location
1594 Bromley Lane, Brighton, Colorado.
Ticket Price
Admission is $5 for adults, $3 for seniors, and free for children under 12.
Parking Information
Free parking is available on-site.
Barr Lake State Park
Overview
Barr Lake State Park, located in the eastern part of Adams County, is not only a popular recreational area but also has historical significance. The lake was originally developed as a water reservoir for agricultural irrigation in the late 19th century. Today, it serves as a state park, offering activities like hiking, fishing, and bird-watching. Barr Lake is known for its diverse bird population, including bald eagles, and features a historical boardwalk that highlights the area’s history of water management and irrigation.
Location
13401 Picadilly Road, Brighton, Colorado.
Ticket Price
A daily pass is $10 per vehicle, and an annual pass is available for $80.
Parking Information
Parking is available at designated lots within the park, and fees are included in the park admission.
County Facts About Adams
Geography and Climate
Adams County covers an area of approximately 1,184 square miles in northeastern Colorado and is part of the Greater Denver metropolitan area. The region encompasses diverse landscapes, including the Rocky Mountain foothills, plains, and waterways like the South Platte River. Adams County experiences a semi-arid climate, with cold, snowy winters and hot, dry summers. Average summer temperatures reach the high 80s °F, while winter temperatures often fall below freezing, with moderate snowfall throughout the season. The county’s diverse climate and geography support agriculture, outdoor recreation, and wildlife habitats.
Key Facts at a Glance
- Year Founded: 1902
- County Seat: Brighton
- Population: Approximately 519,000 (as of the 2020 census)
- Population Density: Around 438 people per square mile
- Largest Cities: Aurora, Thornton, Westminster, Brighton, Commerce City
- Major Highways: Interstate 25, Interstate 70, Interstate 76, U.S. Route 85, U.S. Route 36
- Adjacent Counties:
- Weld County (north)
- Denver County (southwest)
- Arapahoe County (south)
- Jefferson County (west)