diff --git a/applications/utilities/preProcessing/mapFields/mapFields.C b/applications/utilities/preProcessing/mapFields/mapFields.C
index 2f0277417..bd3c36904 100644
--- a/applications/utilities/preProcessing/mapFields/mapFields.C
+++ b/applications/utilities/preProcessing/mapFields/mapFields.C
@@ -275,7 +275,7 @@ int main(int argc, char *argv[])
         (
             IOobject
             (
-                fvMesh::defaultRegion,
+                targetRegionName,
                 runTimeTarget.timeName(),
                 runTimeTarget
             )
@@ -300,7 +300,7 @@ int main(int argc, char *argv[])
             (
                 IOobject
                 (
-                    fvMesh::defaultRegion,
+                    sourceRegionName,
                     runTimeSource.timeName(),
                     runTimeSource
                 )
@@ -342,7 +342,7 @@ int main(int argc, char *argv[])
         (
             IOobject
             (
-                fvMesh::defaultRegion,
+                sourceRegionName,
                 runTimeSource.timeName(),
                 runTimeSource
             )
@@ -365,7 +365,7 @@ int main(int argc, char *argv[])
             (
                 IOobject
                 (
-                    fvMesh::defaultRegion,
+                    targetRegionName,
                     runTimeTarget.timeName(),
                     runTimeTarget
                 )
@@ -446,7 +446,7 @@ int main(int argc, char *argv[])
             (
                 IOobject
                 (
-                    fvMesh::defaultRegion,
+                    sourceRegionName,
                     runTimeSource.timeName(),
                     runTimeSource
                 )
@@ -481,7 +481,7 @@ int main(int argc, char *argv[])
                     (
                         IOobject
                         (
-                            fvMesh::defaultRegion,
+                            targetRegionName,
                             runTimeTarget.timeName(),
                             runTimeTarget
                         )
@@ -523,7 +523,7 @@ int main(int argc, char *argv[])
         (
             IOobject
             (
-                fvMesh::defaultRegion,
+                sourceRegionName,
                 runTimeSource.timeName(),
                 runTimeSource
             )
@@ -533,7 +533,7 @@ int main(int argc, char *argv[])
         (
             IOobject
             (
-                fvMesh::defaultRegion,
+                targetRegionName,
                 runTimeTarget.timeName(),
                 runTimeTarget
             )
diff --git a/applications/utilities/preProcessing/mapFields/setRoots.H b/applications/utilities/preProcessing/mapFields/setRoots.H
index 6aceba234..5964c26ce 100644
--- a/applications/utilities/preProcessing/mapFields/setRoots.H
+++ b/applications/utilities/preProcessing/mapFields/setRoots.H
@@ -2,6 +2,9 @@
     argList::validArgs.clear();
     argList::validArgs.append("source dir");
 
+    argList::validOptions.insert("sourceRegion", "name");
+    argList::validOptions.insert("targetRegion", "name");
+
     argList::validOptions.insert("sourceTime", "scalar");
     argList::validOptions.insert("parallelSource", "");
     argList::validOptions.insert("parallelTarget", "");
@@ -21,8 +24,27 @@
     fileName rootDirSource = casePath.path();
     fileName caseDirSource = casePath.name();
 
-    Info<< "Source: " << rootDirSource << " " << caseDirSource << nl
-        << "Target: " << rootDirTarget << " " << caseDirTarget << endl;
+    word sourceRegionName;
+    word targetRegionName;
+
+    args.optionReadIfPresent
+    (
+        "sourceRegion",
+        sourceRegionName,
+        fvMesh::defaultRegion
+    );
+
+    args.optionReadIfPresent
+    (
+        "targetRegion",
+        targetRegionName,
+        fvMesh::defaultRegion
+    );
+
+    Info<< "Source: " << rootDirSource << " " << caseDirSource
+        << " " << sourceRegionName << nl
+        << "Target: " << rootDirTarget << " " << caseDirTarget
+        << " " << targetRegionName << endl;
 
     bool parallelSource = args.optionFound("parallelSource");
     bool parallelTarget = args.optionFound("parallelTarget");