The “Westminster Abbey of Hawaii,” as it is locally called, Kawaiahao Church was the church of the aliʻi and the Mother Church for the Congregational Mission in Hawaii. Based on typical early-nineteenth-century New England Congregational Church designs, it presents a symmetrical facade to the street with three round-arched portals framed by four pilasters, a pediment-like gable, and an inset central bell tower. Initially, a modest steeple surmounted the clock tower, but in 1885 money designated by Bernice Pauahi Bishop's will allowed the construction of the crenellated square bell tower. The clock was installed in January 1851.
The church measures 78 × 144 feet and took five years to complete. The coral-block walls are thirty-three inches thick and are made of almost fourteen thousand stones ranging in weight from two hundred to twelve hundred pounds. These were quarried by Hawaiians from the reef, as was the lime used in the mortar. Timber came from the Islands, California, and the Pacific Northwest. The windows, boards, and nails were brought from Massachusetts. As the ground could not sustain the weight of such a massive structure, a six-foot-deep foundation was excavated and forty-four-inch-thick, twelve-foot-high basement walls were erected on the solid coral bedrock. The original interior has been altered, the result of renovations in 1894 and 1926–1927.