Question: Ulrich of Eppenstein served as an abbot for an Abbey located in which city in Switzerland ?

Context paragraphs:
Sibton Abbey: Sibton Abbey, an early Cistercian abbey located near Yoxford, Suffolk, was founded about 1150 by William de Chesney, High Sheriff of Norfolk and Suffolk.  A sister house of Warden Abbey, near Bedford, Bedfordshire, Sibton Abbey was the only Cistercian abbey in East Anglia.

Irsee Abbey: Irsee Abbey, also the Imperial Abbey of Irsee (German: "Reichsabtei Irsee" ), was a Benedictine abbey located at Irsee near Kaufbeuren in Bavaria.  The self-ruling imperial abbey was secularized in the course of the German mediatization of 1802–1803 and its territory annexed to Bavaria.  The buildings of the former abbey now house a conference and training centre for Bavarian Swabia.

Abbey of Saint Gall: The Abbey of Saint Gall (German: Abtei St. Gallen ) is a dissolved abbey (747–1805) in a Roman Catholic religious complex in the city of St. Gallen in Switzerland.  The Carolingian-era monastery has existed since 719 and became an independent principality between 9th and 13th centuries, and was for many centuries one of the chief Benedictine abbeys in Europe.  It was founded by Saint Othmar on the spot where Saint Gall had erected his hermitage.  The library at the Abbey is one of the richest medieval libraries in the world.  The city of St. Gallen originated as an adjoining settlement of the abbey.  Following the secularization of the abbey around 1800 the former Abbey church became a Cathedral in 1848.  Since 1983 the whole remaining abbey precinct has been a UNESCO World Heritage Site.

Abbey of Saint-Michel-de-Cuxa: The abbey of Saint-Michel-de-Cuxa (Catalan: "Sant Miquel de Cuixà" ) is a Benedictine abbey located in the territory of the commune of Codalet, in the Pyrénées-Orientales "département", in southwestern France.  It was an important cultural centre in the regency of Abbot Oliba.

Sawtry Abbey: Sawtry Abbey was a Cistercian abbey located between Sawtry and Woodwalton in Cambridgeshire, England.  The abbey was founded in 1147 by Simon II de Senlis, Earl of Northampton, who was the grandson of Earl Waltheof and Judith, the niece of William the Conqueror who held the manor when the Domesday Survey was compiled.  It is the only Cistercian abbey in the county.

Ulrich of Eppenstein: Ulrich of Eppenstein (? ca.1047–1121) served between 1071 and his death as Abbot of the powerful Abbey of Saint Gall.  Ulrich was prominent as a supporter of Emperor Henry IV during the civil wars that erupted out of the power struggles between the emperor and the papacy during the closing decades of the eleventh century.

Säckingen Abbey: Säckingen Abbey is a former Roman Catholic abbey located in Bad Säckingen, Baden-Württemberg in Germany.  The Abbey was founded in the 6th or 7th century by Fridolin of Säckingen, an Irish monk.  While the Abbey had both monks and nuns, only the nuns' convent grew to be an important religious, economic and cultural institution for the entire upper Rhine.

Flaran Abbey: Flaran Abbey is a former Cistercian abbey located in Valence-sur-Baïse, in the "département" of Gers, France.  The abbey was founded in 1151, as a daughter house of Escaladieu Abbey, at the confluence of the Auloue and Baïse rivers, between the towns of Condom and Auch.  The abbey was founded by Burgundian monks and today represents one of the best preserved abbeys in the south-west of France.

Psalmody Abbey: Psalmody Abbey, also Psalmodie Abbey or Psalmodi Abbey (French: "Abbaye de Psalmody, Psalmodi" or "Psalmodie"), was a Benedictine abbey located near Saint-Laurent-d'Aigouze in the Camargue, in the department of Gard and the region of Languedoc-Roussillon in the south of France.

Escaladieu Abbey: Escaladieu Abbey (French: "l'Abbaye de l'Escaladieu") was a Cistercian abbey located in the French "commune" of Bonnemazon in the Hautes-Pyrénées.  Its name derives from the Latin "Scala Dei" ("ladder of God").  The abbey was founded in 1142 and became an important pilgrimage stop on the Way of St. James en route to the Cathedral of Santiago de Compostela.  The abbey is situated at the confluence of the Luz and the Arros rivers near the Château de Mauvezin.

Supporting paragraphs: Ulrich of Eppenstein Abbey of Saint Gall
Answer: St. Gallen