The mansard roof with either concave or straight sides is the key to distinguishing the Second Empire style. Although not extremely common in Colorado, there are examples of this high style, most notably the Tabor Hotel in Leadville, the Bloom House in Trinidad, and the Maxwell House in Georgetown. Characteristics include the mansard roof, a projecting bay or tower extending above the roofline, either contoured or to one side. Windows are pedimented or have molded surrounds. Quoins are found on the Bloom House, along with roof cresting. Cornices are bracketed, reminiscent of the Italianate style.

Vernacular variations are usually found on very small homes. The mansard roof and pedimented windows are generally the major elements of the style visible on these small residences.

The photos depict designated landmarks in Longmont that are representative of the Second Empire style.