Not following fully the traditional Spanish urban town plan of situating the church as the focus of the central town plaza, the location of the Nuesta Señora De La Asunción church and convent in Sta. Maria, Ilocos Sur standing alone on the crown of a freestanding hill encircled by a stone retaining wall gives it a citadel appearance. Its appearance evokes a Mediterranean hill town, the only example of such in the Philippines.
Evoking a Chinese pagoda, the squat and massive bell tower of stacked octagonal shapes of decreasing diameter is crowned by a small dome. From any angle, the approach to the Santa Maria ensemble is magnificent. A stairway of 85 stone steps rises form the town to the small courtyard at the top of the citadel. On the opposite side of the courtyard, another equally grand stairway descends to a causeway built up over rice fields leading to a circular cemetery.
Built of brick, the church has a monumental façade. The thick side walls are without ornamentation, but have delicately carved side entrances which are bolstered regularly by huge quadrangular buttresses, these are necessary structural reinforcements for earthquake protection. The power and simplicity of its geometric forms, and its location, make this an outstanding example of Peripheral Baroque architecture.