right|thumb|200px|Marchlewszczyzna on the map of western part of [[Administrative divisions of Ukraine (1925–1932)|Polissia Subdistrict in 1926]]
right|thumb|200px|Map of the district in 1931
right|thumb|200px|Julian Marchlewski
Marchlewszczyzna (; ) was a Polish National District in the Ukrainian Soviet Socialist Republic created as an experiment on 21 July 1925 by resolution of the Little Presidium of the All-Ukrainian Central Executive Committee. Its capital, the town of Dovbysh, was renamed later in 1926 as Marchlewsk. The district was one of 32 other national districts that were created in the Ukrainian SSR during that period (1924-1939). The function of the Polish District had boldly expressed its political composition, Among such was Jan Trybel, the father of Halyna (Helena) Trybel, who spent 20 years in exile.