Dating from 1898, the four stone charcoal kilns are important as the only remaining intact structures associated with the Bromide Mining and Milling Company’s smelter facility.  The period of intensive operations at the facility extended through the end of World War I.  

The Castle Park Archaeological District is significant in the areas of Prehistoric Archaeology and Architecture, notably for its cultural context representing a cohesive group of sites that were a prehistoric community.  The architecture and artifacts at the site demonstrate that domestic activities were centered on prehistoric agriculture and resource acquisition.

The circa 1911 wood frame rural schoolhouse remained in use as a school until 1947.  After its closure, it continued to function as a community center.  Listed under Rural School Buildings in Colorado Multiple Property Submission.

The district is significant for its diversity and abundance of prehistoric sites dating from the early Archaic period (circa 5000 BC) through the early ceramic period (circa AD 1000).

The community, begun by the Du Pont Company in 1906, and occupied starting in 1908, provided employee housing and support facilities for the adjacent Louviers Works dynamite plant.  Du Pont carefully planned, built, and managed the village. 

The 1875 building is a rare example of a stone depot constructed by the Denver & Rio Grande Railroad.  Castle Rock quarries yielded the high quality rhyolite stone used in the depot’s construction. 

The La Jara Archaeological District is a cultural landscape that represents approximately 10,000 years of human occupation and provides information regarding the cultural groups that have occupied the area throughout the past.

Located in a rugged rural setting, the 1934 filled spandrel arch bridge was designed by the Colorado Department of Highways and built by Gordon Construction Company. 

The Rockvale School represents the community’s efforts to provide education for its children as well as the local coal company’s concern for the education of its adult employees. 

Sanford Amy built the house and associated structures as part of the settlement of the Upper Pleasant Valley in western Fremont County.