[5]: 228  Soon after the parish's formation, a small frame church building was erected on the northeastern corner of the intersection of what is now Cassella-Montezuma Road and State Route 119.

[3] Dominating the church's facade is a square tower at the front; topped with a cupola above an arch-shaped tracery window, it is decorated with ornamental columns.

Nativity is one of the oldest second-generation churches, which were generally small rectangular brick buildings such as Holy Family; although it was built during the years of the first generation,[8]: 2  it assumed its present condition after the 1888 fire.

A square two-story building, its walls are of brick laid in a common bond; they rest on an ashlar foundation and are topped with a hip roof of asphalt shingles.

[9] In the parish's first ten years, Mass was celebrated by errant priests who stayed at nearby convents during their visits; accordingly, there was no need for a rectory.

This situation changed in the earliest years of the twentieth century, when an archiepiscopal directive required all parishes in the Archdiocese of Cincinnati to construct rectories for their pastors.

The resulting houses are generally two-story rectangular brick structures with hip roofs and verandahs; the rectory at Cassella is one of the best-preserved examples of the period.

[8]: 4 Soon after the establishment of the parish, the Sisters of the Precious Blood founded a convent approximately 0.5 miles (0.80 km) south of Cassella.

Although the survey observed that no efforts were being made toward the preservation of the buildings, both were classified as being in good condition on the interior and the exterior, and no threats to their continued existence could be found.