Area
117.14 km²
Population
101,685

Trier (French: Trèves; Luxembourgish: Tréier; Latin: Augusta Treverorum) is a city in Germany on the banks of the Moselle River. It is the oldest city in Germany, founded in or before 16 BC. Trier is not the only city claiming to be Germany's oldest, but it is the only one that bases this assertion on having the longest history as a city, as opposed to a mere settlement or army camp.
Trier lies in a valley between low vine-covered hills of ruddy sandstone in the west of the state of Rhineland-Palatinate, near the German border with Luxembourg and within the important Mosel-Saar-Ruwer wine-growing region.
Trier is the oldest seat of a Christian bishop north of the Alps. In the Middle Ages, the Archbishop of Trier was an important ecclesiastical prince, as the Archbishopric of Trier controlled land from the French border to the Rhine. He was also one of the seven electors of the Holy Roman Empire.
With an approximate population of 100,000, Trier was until 2005 ranked fourth alongside Kaiserslautern among the state's largest cities, after Mainz, Ludwigshafen am Rhein and Koblenz. The nearest large cities in Germany are Saarbrücken, some 80 km southeast, and Koblenz, about 100 km northeast. The closest city to Trier is the capital of Luxembourg, some 50 km to the southwest.
Trier is home to the University of Trier, the administration of the Trier-Saarburg district and the seat of the ADD (Aufsichts- und Dienstleistungsdirektion), which until 1999 was the borough authority of Trier. It is one of the five "central places" of the state of Rhineland-Palatinate. Along with Luxembourg, Metz and Saarbrücken, fellow constituent members of the QuattroPole union of cities, it also forms a central place of the greater region encompassing Saar-Lor-Lux (Saarland, Lorraine and Luxembourg), Rhineland-Palatinate and Wallonia.

Trier is well known for its well-preserved Roman and medieval buildings, which include:

• the Porta Nigra, the best preserved Roman city gate north of the Alps;
  
• ruins of three Roman baths, among them the largest Roman baths north of the Alps;
  
• the huge Constantine Basilica, a basilica in the original Roman sense, being the 67 m long throne hall of Roman Emperor Constantine; it is today used as a Protestant church.
  
• the Trier Cathedral (German: Trierer Dom or Dom St. Peter), a Roman Catholic church which dates back to Roman times and is home to the Holy Tunic, a garment that presumably goes back to the robe Jesus was wearing when he died. It is only exhibited every few decades, at irregular intervals.
  
• the Liebfrauenkirche (German for Church of Our Lady), which is one of the most important early Gothic cathedrals in Germany and follows into the architectural tradition of the French Gothic cathedrals;
  
• the Roman amphitheatre;
  
• the Roman bridge (Römerbrücke) across the Moselle River, which is the oldest bridge north of the Alps still crossed by traffic;
  
• St. Matthew Abbey (Abtei St. Matthias), a still-in-use monastery in whose medieval church the only apostle north of the Alps is held to be buried
  
• St. Gangolf Church was the city's market church that rivalled the Archbishop's Trier Cathedral. 
   

Other edifices of interest include:
the church of St. Paulin, which is one of the most important Baroque churches in Rhineland-Palatinate and may have been in parts designed by the famous architect Balthasar Neumann
the two old treadwheel cranes, the so called "Old Crane" (der Alte Krahnen) or the "Trierian Moselle Crane" (der Trierer Moselkrahn), a Gothic time building from 1413, and the Baroque crane from 1774 called the (old) "Customs Crane" (der (alte) Zollkran), also called the "Younger Moselle Crane" (German: der Jüngere Moselkran).