Dzierżoniów (d͡ʑɛrˈʐɔɲuf; Rychbach; Reichenbach im Eulengebirge ˈʁaɪçn̩bax) is a town located at the foot of the Owl Mountains in southwestern Poland, within the Lower Silesian Voivodeship (from 1975 to 1998 in the former Wałbrzych Voivodeship). It is the seat of Dzierżoniów County, and of Gmina Dzierżoniów (although it is not part of the territory of the latter, since the town forms a separate urban gmina).
Established in the 13th century, Dzierżoniów is a historical Lower Silesian town that covers an area of , and as of December 2021 it has a population of 32,346. It is named after Polish priest and scientist Jan Dzierżon.
Unique and architecturally rich, Dzierżoniów features a central market square with elegant tenements and a town hall as well as few museums and restaurants. The Old Town is a venue for several annual events and fairs.
In its early history until 1945, the town was known as Reichenbach; composed of the German words reich (rich, strong) and Bach (stream), it refers to the current of the Piława River. The name was rendered in Polish as Rychbach. To differentiate between other places named Reichenbach, the Lower Silesian town became known in German as Reichenbach im Eulengebirge, or "Reichenbach in the Owl Mountains".
In the early Middle Ages, the area was inhabited by the tribe of Silesians. After short periods of Great Moravian and Czech rule, in the 10th century the region became part of the emerging Polish state.
Reichenbach was first mentioned in a document dating to 13 February 1258. The parish Church of St. George was also noted early on. The town was part of various Piast-ruled duchies of fragmented Poland. The coat of arms, depicting Saint George slaying a dragon, was used by 1290 at the latest. The town passed successively from the Bishopric of Wrocław, to the Duchy of Ziębice, and to the Duchy of Świdnica-Jawor. The Knights Hospitaller built a school and hospital in the town in 1338. In 1392 the town became part of the Kingdom of Bohemia. It was plundered by the Hussites during the 15th-century Hussite Wars.