The Crystal Valley Parkway and I-25 interchange in southern Castle Rock is fully open, nearly eight months ahead of schedule, the Town of Castle Rock announced. Overnight, the southbound I-25 on- and off-ramps opened, connecting to the new Crystal Valley Parkway bridge and marking the project's final major milestone, the Town said in a Nov. 13, 2026 email. Other portions of the interchange opened in phases.
The Town calls the interchange its No. 1 transportation priority and the largest project of its kind in its history. It sits at Exit 179, and the Town says it has been planned since the 1980s.
What opened, and when
The interchange opened in phases. Per the Town's project timeline:
- January 2025: A new roundabout at Crystal Valley Parkway and East Frontage Road, east of I-25, and the East Frontage Road shifted east to make room for the bridge and northbound ramps.
- November 2025: The new Crystal Valley Parkway bridge over the BNSF Railway tracks and I-25 opened to east-west traffic, along with a new signalized intersection at Dawson Trails Boulevard west of I-25. The West Frontage Road closed permanently and was replaced by Dawson Trails Boulevard.
- July 2026: The northbound I-25 on- and off-ramps opened, the first direct northbound I-25 access to this part of southern Castle Rock.
- November 2026: The southbound ramps, built west of I-25 along the former West Frontage Road alignment, opened, connecting to the bridge through a new signalized intersection.
Landscaping and other finishing work will continue outside the roadway through early 2027.
Cost and funding
The Town says the entire project, including design, right-of-way acquisition and construction, cost about $144.7 million and was completed within budget. CDOT's project page lists the construction cost at $120 million.
Funding sources, per the Town:
- $53.6 million in developer contributions
- $24 million from Douglas County for the interchange, plus $11 million for the West Frontage Road, now named Dawson Trails Boulevard
- $8.9 million grant from the Denver Regional Council of Governments
- $5.4 million BUILD grant from the U.S. Department of Transportation
- $1.7 million in Town electric credits
- $900,000 from BNSF Railway
The Town's project page says the remaining cost comes from its Transportation Capital Fund.
Why it finished early
Construction began in 2024. The Town, Douglas County, CDOT and surrounding developers worked together on the project, with Jacobs Engineering as designer and Kraemer North America leading construction. The Town credits early collaboration under a construction manager/general contractor delivery method, combined with a mild 2025 to 2026 winter, for letting crews speed up key work and deliver the nearly three-year project well ahead of schedule.
What's around it
For more on what's going in near the interchange, see our coverage of the King Soopers at Dawson Trails, the Gold Crown Foundation field house and the Crystal Valley Ranch neighborhood plan. Next door in Castle Pines, the Happy Canyon Road interchange rebuild is just getting started.
Questions go to the project team at [email protected] or 720-733-6097.
Related: What's Being Built in Douglas County: every tracked development and project across the county. · Castle Rock: our town guide.
Sources: Town of Castle Rock email, [email protected], Nov. 13, 2026; Town of Castle Rock, "Crystal Valley interchange complete nearly eight months ahead of schedule", posted Nov. 12, 2026; Town of Castle Rock, Crystal Valley Interchange project page (project schedule, cost, remaining funding, contact); CDOT, I-25 and Crystal Valley interchange project page (construction cost). All checked Nov. 13, 2026.