The Simbirsk Cathedral of the Holy Trinity is considered the most significant historical loss for Simbirsk-Ulyanovsk. Due to its unique architecture and impressive size, it was one of the most valuable temple monuments on the Lower Volga. Together with the older winter cathedral, it formed the basis of the architectural ensemble of the old provincial center. The site for the construction of the cathedral, dedicated to the victory in the Patriotic War of 1812, was chosen in the cathedral square in the center of the historical part of the city. Emperor Alexander I attended the laying of the church on September 7, 1824.

The construction was financed from the remaining funds of the Simbirsk militia, donations from citizens, and loans from the public welfare committee. The cathedral's design was developed by architect Mikhail Petrovich Korinfsky, who was also known for the projects of the cathedral in Arzamas and the main building of Kazan University. His concept was influenced by the unrealized project of the Kazan Cathedral in St. Petersburg, created by his teacher Andrey Voronikhin, but Korinfsky reworked it, giving the cathedral more classical forms.

The cathedral was built in the shape of a massive cross with four colonnades and one main dome, rising above a multi-tiered rotunda. Consecrated on September 15, 1841, the new summer cathedral of the Holy Trinity became the main creation of M. Korinfsky and the first of three major churches dedicated to the victory in the Patriotic War. The other two, the Kazan Cathedral in St. Petersburg and the Cathedral of Christ the Savior in Moscow, were completed later, but the Trinity Cathedral in Simbirsk surpassed them in architectural perfection.

Covering an area of 1388 square meters, the cathedral had three altars: in honor of the Holy Trinity, Alexander Nevsky, and John the Baptist, and after the fire of 1864, in honor of the Third Finding of the Head of John the Forerunner. Among the relics of the cathedral stood out the image of the Savior Not Made by Hands, which had previously been located at the gates of the wooden fortress of Simbirsk. In 1894, during a visit to Simbirsk, John of Kronstadt served the liturgy in the cathedral. Recognized as a masterpiece of classical architecture, the summer Trinity Cathedral was closed in 1930, after which it was used as an archive and preserved as a category 1 architectural monument of Ulyanovsk.

In May 1933, a fire occurred in the cathedral, and its further preservation was deemed impractical. It is believed that in the summer of 1936, the cathedral was blown up. Today, there are no traces left of it, and the Cathedral Square, where it stood, now represents an open area by the upper embankment of the Volga.