A 1977 excavation resulted in the analysis of over 600 artifacts that revealed the site had functioned from approximately AD 350 to AD 1400 as a hunting and foraging station.

Rourke Ranch played a significant role in the settlement and agricultural development of the Purgatoire River area and continues to reflect the interaction of its Hispanic and Anglo-American settlers.  Beginning in the early 1880s, brothers Eugene and James Rourke began acquiring the lands of departing Hispanic farmers and sheep growers, eventually amassing one of the largest cattle ranches in the area.  

Constructed in 1890, the eclectic building almost defies architectural classification.  Primarily Victorian Gothic (as evident by its steeply pitched roof, pointed arched windows, and polychromatic exterior of contrasting materials), the church includes elements from several other styles of the Late Victorian period.  The prominent, albeit short-lived, Trinidad architectural firm of Bulger & Rapp designed the church. 

The well-preserved building, constructed in 1920, is the purest example of the Beaux-Arts inspired styling reflected in Colorado’s post offices.  Listed under U.S. Post Offices in Colorado Thematic Resource.

The bridge spans Reilly Creek as part of an abandoned segment of Colo. Hwy. 12.  It includes three separate spans over the creek and a large single-span overpass for the Denver & Rio Grande Railroad.  

Raton Pass provided the shortest and most practical route from the upper Arkansas Valley to New Mexico.  Both a barrier and a gateway, the Raton Mountains symbolized the Mountain Branch of the Santa Fe Trail.  Although not highly significant in the routine progress of trail development, the Mountain Branch and its most important feature, Raton Pass, played a significant role in military history. 

The work of the prominent architectural firm of Isaac H. and William M. Rapp, the 1907 building is one of only two churches in Trinidad identified as designed by the Rapp brothers’ firm.  A well-preserved example of Romanesque Revival style religious construction in Trinidad, Mount Carmel is also significant for its association with the local Italian American community. 

One of the finest residences erected in early 20th century Trinidad, the noted architectural firm of Isaac Hamilton and William Mason Rapp designed the Nichols House.  The most influential architects in Trinidad, the Rapp brothers designed many of the city’s highly significant buildings, including churches, commercial blocks, and residences.

The 1891 McCormick House is architecturally significant as a good example of a late 19th century distinctive Queen Anne style house.  The house displays the prominent features of the Queen Anne style in its steeply pitched hipped roof with lower cross gable roofs, round tower, balconies, dormers, arched window, decorative fishscale shingles, and overall discontinuity of the vertical wall plane. 

The 1925 Frank Latuda House is architecturally significant as an excellent example of an early twentieth-century distinctive Mediterranean Revival style house. Character-defining features include a red tile, low-pitched hipped roof, arched entrances, light colored brick, and original woodwork, hardware, and fixtures. The Mediterranean Revival is not a common style in Trinidad and the house is the only documented example by the prolific firm of I.H. Rapp, W.M. Rapp and A.C. Hendrickson, Architects.