The Transfiguration Cathedral is the largest structure in the Kremlin ensemble. It was built between 1713 and 1716 on the site of a 15th-century cathedral erected during the reign of Prince Andrei the Great. The Uglich land registry books preserve its description: "A cathedral on high porches with one dome, covered with wooden shingles, and the dome on wooden arches is covered with wooden scales. The church has long had wall writing, and the porch housed a wooden tent-like bell tower with striking hours."

The Transfiguration Cathedral combines features of early 18th-century architecture, merging the traditions of ancient Russian architecture with new techniques. Its composition is dominated by a massive central cube with five domes. The facades are adorned with decorative elements, such as window frames with 'torn' cornices, characteristic of Russian Baroque. The structure of the cathedral reflects the achievements of 18th-century construction, when mainly pillarless churches were built. The impressive size of the central volume, where a fourteen-meter span is covered by a light vault seventeen meters high without supporting columns, places the cathedral among the best structures of Russian architecture of that time. The absence of supporting pylons allowed for the maximum opening of the interior space of the temple, facilitating the placement of large pictorial compositions. The cathedral was painted in 1810-1811 by a guild of serf masters under the guidance of Timofey Medvedev from the village of Teikovo. The painting is distinguished by a high level of craftsmanship, with more than fifty compositions executed based on late Renaissance and Baroque models. The fresco "Transfiguration" depicting the healing of a demoniac is a copy of a painting by Raphael, but the provincial artist exaggerated the master's work, adding external pathos and dynamics. Contrasting colors create a sense of disharmony, while decorative elements such as colonnades and carved cartouches enhance the illusion of space and perspective.

The grand multi-tiered iconostasis of the cathedral was installed in 1860 and varies in forms of "Naryshkin Baroque," although its plasticity is dry. Columns entwined with vines and cornices frame the icons, the oldest of which are located in the lower tiers. The icon "Protection of the Mother of God" is a specimen of the Yaroslavl school of the 17th century. The icons of the festive order were likely painted in the early 18th century simultaneously with the construction of the cathedral. The icons of Christ and the Mother of God in the local row resemble works of Ukrainian Baroque from the 17th century. They entered the cathedral at the turn of the 17th-18th centuries when the Rostov diocese was headed by Metropolitans Josaphat and Dmitry. Next to the cathedral rises a thirty-five-meter bell tower, built in 1730, a decade and a half after the cathedral. The delay in construction may have been related to Peter I's decree of 1714, prohibiting the construction of stone structures in the provinces. The bell tower belongs to the tiered type, and another similar bell tower has been preserved in Uglich at the Korsun Church. Inside the Kremlin bell tower, the mechanism of the tower clock with striking has been preserved, a rare monument of 18th-century clockmaking art. Today it is a museum exhibit. Modern masters from the Uglich Clock Factory have installed electronic striking clocks on the bell tower, and now a melodic chime once again resonates over the city, symbolizing the continuity and development of traditions.