Castle Rock is 535 acres bigger after its town council approved the annexation and rezoning of a longtime cattle ranch west of Founders Parkway.

The move tees up a major new master-planned project called Pine Canyon, set to include 1,800 homes, as much as 600K SF of commercial space and a potential high-end resort and spa.

JRW Family Limited Partnership proposed the project.

The land, split by Interstate 25 and already surrounded by town boundaries, has been in the same family for six generations dating back to an 1885 Homestead Act claim. Since 1909, it has operated as a cattle ranch.

Pine Canyon is expected to bring 800 single-family units east of Interstate 25 and 1,000 multifamily homes along the highway, according to documents submitted to the town council and reported by the Denver Business Journal.

Plans also call for a 21-acre site that could house a 225-room resort and spa, branded residences or, if Castle Rock is unable to find a development partner, 75 additional homes. About 175 acres, or roughly a third of the site, are reserved for parks and open space, including 8.5 miles of trails.

Some residents raised concerns about traffic and infrastructure strain, but the council moved forward, also approving a 50-page site-specific agreement laying out infrastructure, water rights and phasing.

Castle Rock has been on a growth tear for years. The town’s population has surged nearly 17% since 2020, hitting an estimated 87,000 residents by early 2025, according to Census Bureau and town data.