Southbound ramps at the Crystal Valley interchange on I-25 are now open in Castle Rock, completing a project the town says finished eight months ahead of schedule. The milestone gives southern Castle Rock its first full interchange at Crystal Valley Parkway, a route residents have waited decades to see built.
According to the Town of Castle Rock, construction of the southbound ramps was completed in November 2026, following the opening of the northbound on- and off-ramps in July 2026. The town's project page declares the interchange is now open and credits the early finish directly, stating: “The Crystal Valley interchange is now open — eight months ahead of schedule!” Landscaping and other finishing work outside the roadway is expected to continue through early 2027, per the same source.
The timeline marks a shift from earlier projections. A July 2026 update from the town had said the southbound ramps were still under construction and scheduled to open sometime in 2027, and a May 2024 report from Castle Pines Connection indicated the full project was expected to wrap up by mid-2027, with major road construction finished by late 2026. Castle Rock has long described the interchange as a priority: a July 2026 town announcement noted the project “has been planned since the 1980s and is a top transportation priority for the Town.”
Relief for a Road Residents Call a Bottleneck
For years, Crystal Valley residents have relied on the Plum Creek exit and frontage road to reach I-25, as reported by CBS Colorado. Humberto Tiscareno, who owns Fit Body Boot Camp in the Crystal Valley Commons retail complex, told the outlet that frontage road traffic has sometimes been bumper to bumper. Nicole Muller, a Crystal Valley neighbor, said a trip for groceries currently takes 15 to 20 minutes, and a run to Costco can take about 45 minutes with traffic.
Muller told CBS Colorado that the portion of the interchange already open has made her son's school commute to Larkspur five to eight minutes faster, cutting the trip to about 12 minutes from roughly 20. Castle Rock has said traffic will improve further now that the southbound ramps are open, according to the same report.
New Access Point for a Growing Corner of Town
Officially known as I-25 Exit 179, the Crystal Valley interchange provides what the town has called a critical southernmost I-25 connection for Castle Rock, per CBS Colorado's reporting. The project arrives as Douglas County's population has grown almost 24% over the past decade, adding pressure to a stretch of the interstate that previously had no direct interchange serving this part of town.
The interchange is designed to serve both the existing Crystal Valley community and future residents of Dawson Trails, a large mixed-use development taking shape nearby. According to Axios, Dawson Trails is planned to include about 5,850 homes and more than 3 million square feet of commercial space across roughly 2,000 acres, with buildout forecast to take about two decades. The first homes are already underway on the development's west side, CBS Colorado reported, and the former West Frontage Road will become Dawson Trails Boulevard.
Costco, King Soopers and a Medical Campus on the Way
Costco, King Soopers and HCA HealthONE projects have been approved for the area, and Costco is set to open early next year, according to CBS Colorado. Axios reported that a medical campus and additional retail are also expected nearby. Tiscareno told CBS Colorado the Costco arrival will be huge for Castle Rock.
Rippy Bhangu, who owns Crystal Valley Wine & Spirits, invested in the area early, buying land and building the Crystal Valley Commons retail complex in 2020. Bhangu told CBS Colorado the area has grown considerably since he was the only business there.
What the Interchange Cost, and Who Paid for It
Castle Rock's project page lists the total cost of the interchange, including design, right-of-way acquisition and construction, at about $144.7 million. That figure is higher than the roughly $142.4 million estimate reported by Castle Pines Connection in May 2024, when construction on the project's first phase, led by Castle Rock, Douglas County and contractor Kraemer North America, had just begun. CBS Colorado's report separately put the project's cost at $150 million.
Funding came from a mix of public and private sources. Developer contributions funded $53.6 million of the project, per the town's figures, while Castle Pines Connection's 2024 report had cited $50 million specifically from the Dawson Trails developer. Douglas County contributed $24 million toward the interchange and another $11 million for the West Frontage Road, according to CBS Colorado. The U.S. Department of Transportation provided a $5.4 million BUILD grant, the Denver Regional Council of Governments gave $8.9 million, town electric credits added $1.7 million, and BNSF Railway contributed $900,000.
The finished interchange includes a bridge over I-25, ramps in both directions, a second bridge over the BNSF tracks and a relocated frontage road, according to Discover Douglas County. Castle Rock Mayor Jason Gray called the interchange the town's number one transportation project, per CBS Colorado. CBS Colorado also reported that the opening of the northbound ramps earlier this year alleviated traffic by 50% at the Plum Creek interchange, a number that, along with the project's full traffic and travel-time impact, the town says should improve further now that the southbound side has opened as well.
