Prácheňsko (German: Prachens), or Provincia Prachinensis, is the northern region of South Bohemia in the Czech Republic, between Prague and the Austrian border. It was an autonomous region in the southwest of the present Bohemia, created in the late 13th century and abolished by the Austrian Empire's regional reform of 1848.
Its boundaries extended through the Bohemian Forest in the south, towards Budweis (České Budějovice) to the north, close to the town of Příbram, and southwest to Markt Eisenstein (Železná Ruda). Ethnic groups of the region included Jews, Roma, Czechs and Germans and by religion were Roman Catholics and Jews. Today this region comprises three districts, namely West Bohemia, South Bohemia, and Central Bohemia. Its capital city was Pisek (a great medieval city until its devastation in 1620 during the Thirty Years' War), now a town of approximately 30,000 to 35,000 inhabitants.
The first capital, Prachens (which gave its name to the whole region of Prácheň), is now overtaken by forest. It was close to the town of Horažďovice. The local dialect of the western part is still extant as is the use of the bagpipe in the music of the region. The central geographical feature of the Prachens region is the Otava river, or in the local dialect Wotāva. Principal towns of the former Prachens were Strakonice (or Strakonitz in German), Sušice (Schüttenhofen or Setuakaton in its Celtic form), Rožmitál (Rosenthal), Vimperk (Winterberg), Horní Planá (Ober Plan), Železná Ruda (Markt Eisenstein), Kasejovice (Casseudz, Kasejowitz), Protivín (Protiwin) and Horažďovice (Horaschdowitz).
The current population of the region is approximately 200,00 to 250,000 inhabitants. The area suffered serious population losses because of the Expulsion of Germans after World War II (about 25% of the population) and because of the Holocaust (השואה or חורבן). Today the Jewish population is very small and there is no active synagogue.
A unique dialect of the Czech language is spoken in the western part of the region with a large number of German loan words.
The Bohemian historian August Sedlacek wrote extensively about Provincia Prachinensis and Pisek city.