Date | Country | Change |
| 1801 |  Croatia,  Bosnia and Herzegovina,  Slovenia | Diocese of Gornji Tkalec (Croatian Rite) was renamed as Diocese of Križevci |
| 1801.06.01 |  Italy | Diocese of Fossano was suppressed (to Diocese of Mondovì) |
| 1801.07.15 |  Belgium | Diocese of Antwerpen was suppressed (to Metropolitan Archdiocese of Mechelen and Apostolic Vicariate of ’s-Hertogenbosch) |
| 1801.07.15 | Belgium | Metropolitan Archdiocese of Mechelen lost territory to Diocese of Gent |
| 1801.07.15 | Belgium | Diocese of Namur lost territory to Metropolitan Archdiocese of Mechelen |
| 1801.07.15 | Belgium | Diocese of Tournai lost territory to Diocese of Gent |
| 1801.07.15 |  Netherlands | Apostolic Vicariate of Grave–Nijmegen was established (from Diocese of Roermond) |
| 1801.11.29 | Belgium | Diocese of Brugge was suppressed (to Diocese of Gent) |
| 1801.11.29 | Belgium | Diocese of Ieper was suppressed (to Diocese of Cambrai and Diocese of Gent) |
| 1801.11.29 | Belgium | Diocese of Tournai lost territory to Diocese of Arras |
| 1801.11.29 |  France | Diocese of Agde was suppressed (to Diocese of Montpellier) |
| 1801.11.29 | France | Diocese of Aire was suppressed (to Metropolitan Archdiocese of Bordeaux and Diocese of Bayonne) |
| 1801.11.29 | France | Metropolitan Archdiocese of Aix lost territory to Diocese of Digne |
| 1801.11.29 | France | Metropolitan Archdiocese of Albi was suppressed (to Diocese of Montpellier) |
| 1801.11.29 | France | Diocese of Alet was suppressed (to Diocese of Carcassonne) |
| 1801.11.29 | France | Diocese of Alès was suppressed (to Diocese of Avignon and Diocese of Mende) |
| 1801.11.29 | France | Diocese of Aléria was suppressed (to Diocese of Ajaccio) |
| 1801.11.29 | France | Diocese of Amiens lost territory to Diocese of Arras |
| 1801.11.29 | France | Diocese of Angers exchanged territory with Diocese of Le Mans |
| 1801.11.29 | France | Diocese of Apt was suppressed (to Diocese of Avignon and Diocese of Digne) |
| 1801.11.29 | France | Metropolitan Archdiocese of Arles was suppressed (to Metropolitan Archdiocese of Aix) |
| 1801.11.29 | France | Diocese of Arras exchanged territory with Metropolitan Archdiocese of Cambrai |
| 1801.11.29 | France | Metropolitan Archdiocese of Auch was suppressed (to Diocese of Agen) |
| 1801.11.29 | France | Diocese of Autun lost territory to Diocese of Dijon |
| 1801.11.29 | France | Diocese of Auxerre was suppressed (to Diocese of Troyes) |
| 1801.11.29 | France | Metropolitan Archdiocese of Avignon was demoted as Diocese of Avignon (gained territory from the suppressed Diocese of Alès, Diocese of Apt, Diocese of Carpentras, Diocese of Cavaillon, Diocese of Gap, Diocese of Nîmes, Diocese of Orange, Diocese of Saint-Paul-Trois-Châteaux, Diocese of Sisteron, Diocese of Uzès and Diocese of Vaison and became suffragan of Aix) |
| 1801.11.29 | France | Diocese of Avranches was suppressed (to Diocese of Coutances) |
| 1801.11.29 | France | Diocese of Bayeux exchanged territory with Diocese of Coutances |
| 1801.11.29 | France | Diocese of Bazas was suppressed (to Metropolitan Archdiocese of Bordeaux and Diocese of Agen) |
| 1801.11.29 | France | Diocese of Beauvais was suppressed (to Diocese of Amiens) |
| 1801.11.29 | France | Diocese of Belley was suppressed (to Metropolitan Archdiocese of Lyon, Diocese of Chambéry and Diocese of Grenoble) |
| 1801.11.29 | France | Metropolitan Archdiocese of Besançon lost territory to Diocese of Dijon |
| 1801.11.29 | France | Diocese of Bethléem à Clamecy was suppressed (to Diocese of Autun) |
| 1801.11.29 | France | Diocese of Blois was suppressed (to Diocese of Orléans) |
| 1801.11.29 | France | Diocese of Boulogne was suppressed (to Diocese of Arras) |
| 1801.11.29 | France | Diocese of Béziers was suppressed (to Diocese of Montpellier) |
| 1801.11.29 | France | Metropolitan Archdiocese of Cambrai was demoted as Diocese of Cambrai (gained territory from the suppressed Diocese of Ieper and Diocese of Saint-Omer, lost territory to Metropolitan Archdiocese of Mechelen, exchanged territory with Diocese of Arras and Diocese of Tournai and became suffragan of Paris) |
| 1801.11.29 | France | Diocese of Carpentras was suppressed (to Diocese of Avignon) |
| 1801.11.29 | France | Diocese of Castres was suppressed (to Diocese of Montpellier) |
| 1801.11.29 | France | Diocese of Cavaillon was suppressed (to Diocese of Avignon) |
| 1801.11.29 | France | Diocese of Chartres was suppressed (to Diocese of Séez and to establish Diocese of Versailles) |
| 1801.11.29 | France | Diocese of Châlon-sur-Saône was suppressed (to Diocese of Autun and Diocese of Dijon) |
| 1801.11.29 | France | Diocese of Châlons-sur-Marne was suppressed (to Diocese of Meaux) |
| 1801.11.29 | France | Diocese of Clermont exchanged territory with Diocese of Saint-Flour |
| 1801.11.29 | France | Diocese of Condom was suppressed (to Diocese of Agen) |
| 1801.11.29 | France | Diocese of Couserans was suppressed (to Metropolitan Archdiocese of Toulouse) |
| 1801.11.29 | France | Diocese of Coutances exchanged territory with Diocese of Bayeux |
| 1801.11.29 | France | Diocese of Dax was suppressed (to Diocese of Bayonne) |
| 1801.11.29 | France | Diocese of Die was suppressed (to Diocese of Grenoble and Diocese of Valence) |
| 1801.11.29 | France | Diocese of Dol was suppressed (to Diocese of Évreux, Diocese of Quimper, Diocese of Rennes and Diocese of Saint-Brieuc) |
| 1801.11.29 | France | Metropolitan Archdiocese of Embrun was suppressed (to Diocese of Digne) |
| 1801.11.29 | France | Diocese of Fréjus was suppressed (to Metropolitan Archdiocese of Aix) |
| 1801.11.29 | France | Diocese of Gap was suppressed (to Diocese of Avignon, Diocese of Digne, Diocese of Grenoble and Diocese of Valence) |
| 1801.11.29 | France | Diocese of Glandèves was suppressed (to Diocese of Digne and Diocese of Nice) |
| 1801.11.29 | France | Diocese of Grasse was suppressed (to Metropolitan Archdiocese of Aix) |
| 1801.11.29 | France,  Saint Pierre and Miquelon | Diocese of La Rochelle exchanged territory with Diocese of Nantes and Diocese of Poitiers |
| 1801.11.29 | France | Diocese of Langres was suppressed (to Diocese of Dijon and Diocese of Troyes) |
| 1801.11.29 | France | Diocese of Laon was suppressed (to Diocese of Metz and Diocese of Soissons) |
| 1801.11.29 | France | Diocese of Lavaur was suppressed (to Diocese of Montpellier) |
| 1801.11.29 | France | Diocese of Le Mans lost territory to Metropolitan Archdiocese of Tours, Diocese of Orléans and Diocese of Séez |
| 1801.11.29 | France | Diocese of Le Puy-en-Velay was suppressed (to Diocese of Clermont and Diocese of Saint-Flour) |
| 1801.11.29 | France | Diocese of Lectoure was suppressed (to Metropolitan Archdiocese of Toulouse and Diocese of Agen) |
| 1801.11.29 | France | Diocese of Lescar was suppressed (to Diocese of Bayonne) |
| 1801.11.29 | France | Diocese of Limoges lost territory to Diocese of Angoulême |
| 1801.11.29 | France | Diocese of Lisieux was suppressed (to Diocese of Bayeux, Diocese of Évreux and Diocese of Séez) |
| 1801.11.29 | France | Diocese of Lombez was suppressed (to Metropolitan Archdiocese of Toulouse and Diocese of Bayonne) |
| 1801.11.29 | France | Diocese of Luçon was suppressed (to Diocese of La Rochelle and Diocese of Nantes) |
| 1801.11.29 | France | Diocese of Léon was suppressed (to Diocese of Quimper) |
| 1801.11.29 | France | Diocese of Mariana et Acci was suppressed (to Diocese of Ajaccio) |
| 1801.11.29 | France | Diocese of Marseille was suppressed (to Metropolitan Archdiocese of Aix) |
| 1801.11.29 | France | Diocese of Meaux exchanged territory with Diocese of Soissons |
| 1801.11.29 | France | Diocese of Metz lost territory to Diocese of Mainz, Diocese of Nancy and Diocese of Strasbourg |
| 1801.11.29 | France | Diocese of Mirepoix was suppressed (to Metropolitan Archdiocese of Toulouse and Diocese of Carcassonne) |
| 1801.11.29 | France | Diocese of Montauban was suppressed (to Metropolitan Archdiocese of Toulouse, Diocese of Agen and Diocese of Cahors) |
| 1801.11.29 | France | Diocese of Mâcon was suppressed (to Metropolitan Archdiocese of Lyon and Diocese of Autun) |
| 1801.11.29 | France | Diocese of Nantes lost territory to Diocese of Angers and Diocese of Vannes |
| 1801.11.29 | France | Metropolitan Archdiocese of Narbonne was suppressed (to Diocese of Carcassonne and Diocese of Montpellier) |
| 1801.11.29 | France | Diocese of Nebbio was suppressed (to Diocese of Ajaccio) |
| 1801.11.29 | France | Diocese of Nevers was suppressed (to Metropolitan Archdiocese of Bourges and Diocese of Autun) |
| 1801.11.29 | France | Diocese of Noyon was suppressed (to Diocese of Amiens and Diocese of Soissons) |
| 1801.11.29 | France | Diocese of Nîmes was suppressed (to Diocese of Avignon) |
| 1801.11.29 | France | Diocese of Oloron was suppressed (to Diocese of Bayonne) |
| 1801.11.29 | France | Diocese of Orange was suppressed (to Diocese of Avignon and Diocese of Valence) |
| 1801.11.29 | France | Diocese of Pamiers was suppressed (to Metropolitan Archdiocese of Toulouse) |
| 1801.11.29 | France | Metropolitan Archdiocese of Paris lost territory to Diocese of Troyes |
| 1801.11.29 | France | Diocese of Perpignan–Elne was suppressed (to Diocese of Carcassonne) |
| 1801.11.29 | France | Diocese of Poitiers lost territory to Diocese of Angoulême |
| 1801.11.29 | France | Diocese of Périgueux was suppressed (to Diocese of Angoulême) |
| 1801.11.29 | France | Diocese of Quimper lost territory to Diocese of Saint-Brieuc |
| 1801.11.29 | France | Metropolitan Archdiocese of Reims was suppressed (to Diocese of Meaux and Diocese of Metz) |
| 1801.11.29 | France | Diocese of Rennes exchanged territory with Diocese of Nantes |
| 1801.11.29 | France | Diocese of Rieux was suppressed (to Metropolitan Archdiocese of Toulouse) |
| 1801.11.29 | France | Diocese of Riez was suppressed (to Metropolitan Archdiocese of Aix and Diocese of Digne) |
| 1801.11.29 | France | Diocese of Rodez was suppressed (to Diocese of Cahors and Diocese of Saint-Flour) |
| 1801.11.29 | France | Metropolitan Archdiocese of Rouen lost territory to Diocese of Amiens and Diocese of Évreux |
| 1801.11.29 | France | Diocese of Sagone was suppressed (to Diocese of Ajaccio) |
| 1801.11.29 | France | Diocese of Saint-Bertrand-de-Comminges was suppressed (to Metropolitan Archdiocese of Toulouse and Diocese of Bayonne) |
| 1801.11.29 | France | Diocese of Saint-Brieuc exchanged territory with Diocese of Vannes |
| 1801.11.29 | France | Diocese of Saint-Claude was suppressed (to Metropolitan Archdiocese of Besançon) |
| 1801.11.29 | France | Diocese of Saint-Dié was suppressed (to Diocese of Nancy) |
| 1801.11.29 | France | Diocese of Saint-Flour exchanged territory with Diocese of Clermont |
| 1801.11.29 | France | Diocese of Saint-Jean-de-Maurienne was suppressed (to Diocese of Chambéry) |
| 1801.11.29 | France | Diocese of Saint-Malo was suppressed (to Diocese of Rennes, Diocese of Saint-Brieuc and Diocese of Vannes) |
| 1801.11.29 | France | Diocese of Saint-Omer was suppressed (to Diocese of Arras and Diocese of Cambrai) |
| 1801.11.29 | France | Diocese of Saint-Papoul was suppressed (to Metropolitan Archdiocese of Toulouse and Diocese of Carcassonne) |
| 1801.11.29 | France | Diocese of Saint-Paul-Trois-Châteaux was suppressed (to Diocese of Avignon and Diocese of Valence) |
| 1801.11.29 | France | Diocese of Saint-Pons-de-Thomières was suppressed (to Diocese of Montpellier) |
| 1801.11.29 | France | Diocese of Saintes was suppressed (to Diocese of Angoulême, Diocese of La Rochelle and Diocese of Poitiers) |
| 1801.11.29 | France | Diocese of Sarlat was suppressed (to Diocese of Angoulême) |
| 1801.11.29 | France | Diocese of Senez was suppressed (to Metropolitan Archdiocese of Aix, Diocese of Digne and Diocese of Nice) |
| 1801.11.29 | France | Diocese of Senlis was suppressed (to Diocese of Amiens and Diocese of Meaux and to establish Diocese of Versailles) |
| 1801.11.29 | France | Metropolitan Archdiocese of Sens was suppressed (to Diocese of Troyes) |
| 1801.11.29 | France | Diocese of Sisteron was suppressed (to Diocese of Avignon, Diocese of Digne and Diocese of Valence) |
| 1801.11.29 | France | Diocese of Soissons exchanged territory with Diocese of Meaux |
| 1801.11.29 | France | Diocese of Séez lost territory to Diocese of Bayeux |
| 1801.11.29 | France | Diocese of Tarbes was suppressed (to Diocese of Agen and Diocese of Bayonne) |
| 1801.11.29 | France | Metropolitan Archdiocese of Tarentaise was suppressed (to Diocese of Chambéry) |
| 1801.11.29 | France | Diocese of Toul was suppressed (to Diocese of Nancy) |
| 1801.11.29 | France | Diocese of Toulon was suppressed (to Metropolitan Archdiocese of Aix) |
| 1801.11.29 | France | Diocese of Tréguier was suppressed (to Diocese of Quimper and Diocese of Saint-Brieuc) |
| 1801.11.29 | France | Diocese of Tulle was suppressed (to Diocese of Limoges) |
| 1801.11.29 | France | Diocese of Uzès was suppressed (to Diocese of Avignon and Diocese of Mende) |
| 1801.11.29 | France | Diocese of Vabres was suppressed (to Diocese of Cahors and Diocese of Montpellier) |
| 1801.11.29 | France | Diocese of Vaison was suppressed (to Diocese of Avignon) |
| 1801.11.29 | France | Diocese of Vannes lost territory to Diocese of Rennes |
| 1801.11.29 | France | Diocese of Vence was suppressed (to Metropolitan Archdiocese of Aix) |
| 1801.11.29 | France | Diocese of Verdun was suppressed (to Diocese of Nancy) |
| 1801.11.29 | France | Diocese of Versailles was established (from Metropolitan Archdiocese of Paris and Metropolitan Archdiocese of Rouen, from the suppressed Diocese of Chartres and Diocese of Senlis and became suffragan of Paris) |
| 1801.11.29 | France | Metropolitan Archdiocese of Vienne was suppressed (to Diocese of Grenoble and Diocese of Valence) |
| 1801.11.29 | France | Diocese of Viviers was suppressed (to Diocese of Mende) |
| 1801.11.29 | France | Diocese of Évreux exchanged territory with Diocese of Séez |
| 1801.11.29 |  Germany | Diocese of Aachen was established (from Metropolitan Archdiocese of Köln, Diocese of Liège, Diocese of Münster and Mission sui juris of Batavia, from the suppressed Diocese of Roermond and became suffragan of Mechelen) |
| 1801.11.29 | Germany | Metropolitan Archdiocese of Mainz was demoted as Diocese of Mainz (gained territory from Metropolitan Archdiocese of Trier, Diocese of Metz and Diocese of Worms, exchanged territory with Diocese of Speyer and became suffragan of Mechelen) |
| 1801.11.29 | Germany | Diocese of Speyer lost territory to Diocese of Strasbourg |
| 1801.11.29 | Germany | Metropolitan Archdiocese of Trier was demoted as Diocese of Trier (lost territory to Metropolitan Archdiocese of Köln, Diocese of Mainz, Diocese of Metz and Diocese of Namur and became suffragan of Mechelen) |
| 1801.11.29 | Germany | Diocese of Worms lost territory to Diocese of Mainz and Diocese of Speyer |
| 1801.11.29 | Netherlands | Diocese of Roermond was suppressed (to Apostolic Vicariate of Grave–Nijmegen and to establish Diocese of Aachen) |
| 1801.11.29 |  Switzerland | Diocese of Basel lost territory to Diocese of Strasbourg |
| 1801.11.29 | Switzerland | Diocese of Genève was suppressed (to Diocese of Chambéry) |
| 1801.11.29 | Switzerland | Diocese of Lausanne lost territory to Metropolitan Archdiocese of Besançon and Diocese of Basel |
