The Assumption Cathedral is an outstanding monument of cult architecture in the Kostroma region from the mid-17th century. It features an original volumetric composition and decor that is oriented towards earlier architecture. The cathedral is a massive rectangular structure with a multi-pitched roof, topped with five helmet-shaped domes on cylindrical light drums. To the east, three lowered rounded apses adjoin the main volume, while to the west, a low porch rises, above which stands a massive bell tower, topped with a tent roof. The southern facade is partially hidden by the Paisievsky chapel, whose altar is aligned with the apses of the main church.

Despite the overall orientation of the cathedral's forms towards 17th-century architecture, the facade divisions do not correspond to the internal structure. The side facades, with a three-part division of the internal space and three zakomaras, are divided into four sections by smooth pilasters. The zakomaras, cut off from the wall by a profiled cornice, do not match the ceiling structure. The composition of the altar part also does not correspond to the internal structure, as almost half of the altar space is included in the volume of the quadrilateral, and the lowered apses have a slight overhang. The cathedral is surrounded by a profiled plinth, and the arched windows on the side facades are placed in deep embrasures. Three keel-shaped portals lead into the church, of which only the northern one opens onto the facade, while the other two are hidden by the western porch and the Paisievsky chapel. Above the windows of the apses, divided by pilasters and topped with a cornice with a belt of a ledge, there are small rectangular niches with triangular pediments. To the right of the main window on the central apse, there is a second, smaller window. At the base of the cylindrical drums of the domes, the central one of which is decorated with an arcature-columned belt, there are semi-circular kokoshniks. The decor of the bell tower is limited to surrounding pilasters and simple cornices at the corners, as well as recessed outlines of the ringing arches. The diagonal faces of the tent are adorned with small dormer windows in frames with triangular pediments. The facade decoration of the Paisievsky chapel is typical of late classicism: a profiled plinth, large windows with sills and semi-circular lintels, smooth pilasters in wide intercolumns, and a simple three-part entablature.

The walls of the temple are currently whitewashed. On the southern wall, there is an arcosolium above the relics of Paisius of Galich. The southern column is hewn, and here was the gilded abbot's place with four twisted columns supporting a conical finish topped with a mitre. The partially preserved baroque stucco decor, consisting of profiled frames, casings, and floral garlands, dates back to the late 18th century. It is likely that the wooden double-leaf doors depicting Paisius and Jacob of Galich, with renewed paintings, also date from this time.