The Church of the Holy Trinity in Mikstat is the town's main parish church, dating back to the 14th century, when the first residents built a wooden church on the so-called Church Hill. Over the centuries, the church was rebuilt several times after fires and destruction, until the current brick church in the neo-Baroque style, designed by Marian Andrzejewski, was built in 1914. It was consecrated by Cardinal Edmund Dalbor in 1918, an event not only religious but also patriotic – the streets of Mikstat were decorated with white and red banners, and young people welcomed the distinguished guest in national costumes.
The church is impressive in its architecture – the three-nave main body is enclosed on the eastern side by a semicircular apse, while a tall tower with a ground-floor porch, topped by a metal dome with a lantern and a cross, dominates the west. The entrance portal is adorned with sculptures of angels and flanked by columns, giving the building a monumental character. The church interior is divided by arcades, the vaults of which are adorned with rich polychrome and stucco decorations. In the western part is a brick choir loft with an organ case, supported by three arcades. The organ, built by Józef Bach in 1939, is unique in Poland.
The church's furnishings are in the spirit of neo-Baroque – the main altar features a bas-relief depicting the Holy Trinity, flanked by scenes of the Annunciation of the Archangel Gabriel and the fight of the Archangel Michael with the dragon. The side altars are dedicated to St. Agatha and the Virgin Mary with the Infant Jesus. A canopied pulpit, the Stations of the Cross, and numerous stained glass windows from 1914 complete the interior's sacred atmosphere. In the church cemetery stands a 19th-century wooden cross, the work of Paweł Bryliński, decorated with sculptures of the Virgin Mary, saints and a pelican feeding its chicks – a symbol of Christ.