Drohiczyn ([drɔˈxʲit͡ʂɘn]) (Lithuanian: Drohičinas/Drogičinas, Belarusian: Дарагічын, romanized: Darahichyn) is a town in Siemiatycze County, Podlaskie Voivodeship, Poland. The town has a population of 2,110 and is situated on the bank of the Bug River. Drohiczyn has a long and rich history, as in the past it was one of the most important cities of the region of Podlachia. Currently, it is the seat of the Roman Catholic Diocese of Drohiczyn.

A Neolithic settlement, La Tène culture crematoria, and ancient graves have been uncovered in what now is Drohiczyn. Drohiczyn, regarded as one of the oldest towns of the region of Podlasie, was in ancient times located among dense forests.

In early Middle Ages, the town's territory was inhabited by the warring tribe of Yotvingians. It is not known who founded the Drohiczyn gord: it was most likely a defensive settlement of the Yotvingians, mentioned in Rus' chronicles in 1061. In 1142, Grand Duke Vsevolod II of Kiev divided his realm between his family, granting Drohiczyn (as Dorohychin) and Brest to his younger brother Igor. Some time in late 12th century, Drohiczyn was under the Polish rule. On March 8, 1237, Duke Konrad I of Masovia handed Drohiczyn, together with the area between the Bug and the Narew, to the Order of Dobrzyń. In March 1238, Prince Daniel successfully annexed Drohiczyn into Galicia-Volhynia after defeating Dobrzyń knights.

In 1241, taking advantage of the chaos which ensued after the Mongol Invasion of Poland, Lithuanian Grand Duke Mindaugas captured Podlasie together with Drohiczyn, Bielsk Podlaski, Mielnik, Brańsk and Suraż, annexing it into the Grand Duchy of Lithuania. The Rus dukes did not want to give up this region, and regained Drohiczyn after a few years. In 1251, Rus forces, gathered at Drohiczyn, invaded the Yotvingians. After a victorious war, the position of Duke Daniel of Galicia grew so strong that he was crowned the King of Ruthenia. This happened in Drohiczyn in 1253.

In 1274, Drohiczyn was again captured by the Lithuanians, and the town with whole province remained in Lithuania until the Union of Lublin (1569), with the exception in the 1380s and 1430s, when Drohiczyn was ruled by the Duke of Masovia Janusz. The Lithuanian duke Jonas Vaidutis was born in the town in 1367 and titled himself the Duke of Drohiczyn.

Drohiczyn was one of major cities of the Grand Duchy of Lithuania, together with Trakai, Vilnius and Navahrudak. In the 15th century, most of town’s population was of Ruthenian heritage, with Polish, Jewish and Lithuanian minorities. In 1498, its position was officially recognized, when it was granted Magdeburg rights.

During the reign of Sigismund I the Old, Drohiczyn was named capital and administrative seat of Podlasie Voivodeship, which was established in 1513. Local sejmiks took place here. At that time, the town experienced its golden age. In 1569 with the Union of Lublin, Drohiczyn was annexed to the Kingdom of Poland. The town continued to prosper, despite a plague outbreak in 1624, which decimated the population. Furthermore, in the 1630s there were two fires, in which several houses burned. Since mid-1630s, the population of Drohiczyn began to decline.

The Deluge (1655–1660) brought widespread destruction and misery, after which Drohiczyn never recovered to its former greatness. Swedish soldiers, led by Magnus Gabriel De la Gardie appeared in the town in August 1655. They immediately looted Drohiczyn, ordering its residents to pay an enormous contribution. In late 1655, a unit of Crimean Tatars, allied with Poland, appeared in the area of Drohiczyn and spent whole winter here, looting all farms and the town.