Hugh IV of Nordgau (970 – 1048) was count of Nordgau, Eguisheim and Dabo. He and his wife patronized numerous abbeys and monasteries. His son Bruno, became Pope Leo IX in 1048.
Hugh was the son of Hugh II of Nordgau. According to Nicolas Viton of Saint-Allais, he succeeded in 1027 his nephew Eberhard VI, who had died childless. In the same year Ernest II, Duke of Swabia, rebelled against his stepfather, the Salic Emperor Conrad II, and Hugh's lands and castles in Alsace were devastated and plundered, before he was forced to surrender and was imprisoned.
Hugh IV was the first cousin of the Salic Emperor Conrad II, because this sovereign's mother, Adelaide, was the sister of his father Hugh II of Nordgau. He founded the Abbey of Hesse, to honour Blessed Bishop Martin, near Sarrebourg, whose privileges were confirmed by his son, Pope Leo IX in 1050. In Altdorf, Hugh had a monastery dedicated to the martyr Cyriacus. He also founded the Abbey of Woffenheim, while his wife, Hedwig of Dabo, founded the Abbey of Notre- Dame d'Oelenberg near Reiningue.
Hugh died in 1048, while his wife had died two years earlier, in 1046.
Hugh IV married Hedwig of Dabo, daughter and heiress of Louis, Count of Dachsbourg. They had: