Denver metro · County guide

Adams County

A 72-mile plains county running from Denver's north edge to the eastern prairie, wrapped around DIA.

Where it is

Adams County covers the metro's north and northeast quadrant, beginning at Denver's northern boundary near Sheridan Boulevard and running 72 miles east past Denver International Airport to the open plains. It holds no foothills at all: its western edge stops well short of the hogbacks, so the Front Range reads as a horizon line rather than as terrain inside the county.

Weld County to the north, Morgan County to the northeast, Washington County to the east, Arapahoe County to the south, the City and County of Denver to the southwest, Jefferson County to the west, and Broomfield to the northwest. Aurora, Arvada, Westminster, Brighton, Bennett and Lochbuie all straddle a county line, so a single city name can mean two different counties.

From downtown Denver

About 10 minutes north to the county line on I-25 or I-76, 25 to 35 minutes northeast to Brighton via I-76 and US-85, and roughly 45 minutes due east to Strasburg on I-70.

Elevation

The low ground is the South Platte valley, with Brighton at 4,987 feet, and the land climbs in both directions from the river: west toward Federal Heights and Westminster, and east to Bennett at 5,486 feet on the divide between the Platte and Republican drainages. Nothing in the county is high enough to change the snow pattern much, but the eastern third has no windbreak, so I-70 past Watkins closes for blowing snow when the metro roads stay clear.

What makes it different

Six things that are true here and not one county over.

How it got here

1. 1881

   Daniel F. Carmichael bought 240 acres from the railroad and filed the first plat for Brighton on February 16, 1881, at the junction of the Denver Pacific and the Denver and Boulder Valley lines. The spot had been called Hughes Station, and the Union Pacific had put a depot there in 1870.

2. 1902

   The legislature voted in 1901 to split Arapahoe County, but a Colorado Supreme Court ruling and a referendum delayed the creation of Adams County until November 15, 1902. It was named for Governor Alva Adams, and the eastern 88 miles of the original 160-mile county went to the new Washington and Yuma counties on May 12, 1903, leaving today's 72-mile strip. Voters made Brighton the permanent county seat on November 8, 1904.

3. 1917

   Farmers and merchants persuaded Great Western Sugar to build a beet processing factory in Brighton after the area committed 5,000 acres to sugar beets. The plant ran until 1977, and the Kuner Pickle Company canned the valley's cucumbers and vegetables alongside it.

4. 1942

   The Army built the Rocky Mountain Arsenal northeast of Denver as a chemical weapons plant, later leasing part of the idle plant to Shell for agricultural chemicals. The deep disposal well drilled in 1961 set off the 1962 to 1967 earthquake sequence, and the site was designated a national wildlife refuge in 1992.

5. 1952 to 1961

   Sam Hoffman bought 400 acres in 1952 and the first three Thornton homes were finished in 1953, the county's first fully planned community, which reached 5,500 residents in nearly 1,200 homes by the end of 1955. Perl-Mack broke ground on Northglenn in 1959, drawing more than 15,000 people to five show homes at what is now I-25 and 104th, and Life magazine and the National Association of Home Builders called it the most perfectly planned community in America in 1961.

6. 2001 to 2020

   The county's northwest tip went to the new City and County of Broomfield on November 15, 2001. Arsenal cleanup finished in 2010, the county's Watkins airfield was licensed as a spaceport in 2018, and RTD's N Line opened from Union Station to 124th Avenue in Thornton on September 21, 2020, with the final 5.5 miles toward State Highway 7 still unfunded.

The towns inside it

What the housing looks like

The oldest stock sits in Brighton's original townsite around Bridge Street, where brick and frame houses from the 1880s through the 1920s stand near the old Union Pacific depot and the 1906 courthouse that is now Brighton City Hall, with farmsteads scattered along the South Platte and the Burlington Ditch. The volume years were the 1950s and 1960s: compact brick and frame ranches laid out on Denver's continuing section-line grid through Welby, Derby, Berkley, Sherrelwood and North Washington, then the planned tracts of Thornton, whose first three homes were finished in 1953, and Northglenn from 1959, mostly ranches and split-levels of roughly 1,000 to 1,500 square feet with attached single-car garages and curvilinear streets around a shopping center. From the 1990s onward construction moved north and east into two-story production housing: Brighton, Commerce City's Reunion and Buffalo Run, Thornton above 120th and later above 144th, Todd Creek's large-lot subdivisions, and most recently the Aurora Highlands near E-470 and Peña Boulevard. East of the airport the pattern breaks entirely, because Colorado's Senate Bill 35, effective May 5, 1972, exempts parcels of 35 acres and larger from county subdivision review, though county zoning still applies and the exemption does not cover multiple residences on one parcel. Platted subdivisions there give way to farmsteads, manufactured homes and 35-acre tracts on wells and septic around Watkins, Bennett and Strasburg.

The events board

Community events that come back every year. Each card links to the organiser for this year's exact date.