Gruta is a rural municipality located in the Kuyavian-Pomeranian Voivodeship, within the Grudziądz County, with its administrative seat in the village of Gruta. The municipality covers an area of 123.77 km², of which 80% is agricultural land and 8% is forested. The area is significant from a nature conservation perspective, as it includes part of the Dolina Osy Nature Reserve, which protects the unique ecological system of the Osa River. In 2004, the municipality had a population of 6,595 residents.
Notably, Gruta boasts a wealth of historical monuments that reflect the region's rich heritage. These include 14th-century churches in Dąbrówka Królewska and Gruta, the ruins of a defensive manor in Boguszewo, and a manor park in Mełno with an extensive palace complex. The municipality also takes pride in the relics of a cemetery in Annów and the ruins of a 13th-century castle in Pokrzywno. Historic parks and manors, many dating back to the late 19th century, bear witness to the cultural flourishing of the region in past centuries.
Gruta is well-connected by a network of roads, including routes 533, 534, and 538, as well as railway lines, facilitating access to nearby towns and larger cities. The administrative villages comprising the municipality include Dąbrówka Królewska, Mełno, Okonin, and Salno, making Gruta an interesting destination not only for its natural attractions but also for its historical and architectural richness. The municipality not only preserves its historical legacy but also continues to develop as a vibrant community for its residents.