Dealing with a pest problem in Castle Rock? You're not alone. mice, voles, ants are among the most common household pests in the Colorado Front Range — and they're active year-round.
Castle Rock sits at 6,224 feet on Douglas County's expansive clay soils — the same bentonite formations that shift foundations also create persistent cracks and settling gaps that give mice easy entry. The city's rapid growth has pushed development into open ponderosa terrain to the west, and field mice displaced by new construction routinely show up in garages and crawl spaces in neighborhoods like The Meadows, Terrain, and Crystal Valley.
spring
Ants emerge as soil warms. Wasp queens begin scouting for nest sites. Mice move back outdoors but may still enter structures.
summer
Peak wasp and ant activity. Brown recluse and black widow spiders active. Voles damage lawns and garden beds.
fall
Primary rodent season — mice and voles seek indoor shelter as temperatures drop below 40°F. Boxelder bugs congregate on south-facing walls.
winter
Indoor rodent activity peaks. Overwintering insects shelter in wall voids and attic spaces.
Castle Rock is the fastest-growing large city in Colorado and one of the fastest-growing in the country. Douglas County, where it sits, consistently ranks as one of the wealthiest counties in the United States.