diff --git a/mercurial/configitems.py b/mercurial/configitems.py
--- a/mercurial/configitems.py
+++ b/mercurial/configitems.py
@@ -1038,6 +1038,9 @@
 coreconfigitem('ui', 'interface.chunkselector',
     default=None,
 )
+coreconfigitem('ui', 'localobsolescence',
+    default=True,
+)
 coreconfigitem('ui', 'logblockedtimes',
     default=False,
 )
diff --git a/mercurial/obsolete.py b/mercurial/obsolete.py
--- a/mercurial/obsolete.py
+++ b/mercurial/obsolete.py
@@ -98,6 +98,7 @@
 createmarkersopt = 'createmarkers'
 allowunstableopt = 'allowunstable'
 exchangeopt = 'exchange'
+localonlymodeopt = 'localonly'
 
 def _getoptionvalue(repo, option):
     """Returns True if the given repository has the given obsolete option
@@ -139,6 +140,15 @@
     createmarkersvalue = _getoptionvalue(repo, createmarkersopt)
     unstablevalue = _getoptionvalue(repo, allowunstableopt)
     exchangevalue = _getoptionvalue(repo, exchangeopt)
+    localonlyvalue = repo.ui.configbool('ui', 'localobsolescence')
+
+    # Evolution options take precedence over local only mode.
+    if createmarkersvalue or unstablevalue or exchangevalue:
+        localonlyvalue = False
+
+    # We /could/ have local only mode imply createmarkers, but this would
+    # have significant implications in core. For now, wait until core
+    # consumers are aware of local only mode before implying this option.
 
     # createmarkers must be enabled if other options are enabled
     if ((unstablevalue or exchangevalue) and not createmarkersvalue):
@@ -149,6 +159,7 @@
         createmarkersopt: createmarkersvalue,
         allowunstableopt: unstablevalue,
         exchangeopt: exchangevalue,
+        localonlymodeopt: localonlyvalue,
     }
 
 def isenabled(repo, option):