diff --git a/openmc/cell.py b/openmc/cell.py
index 6de8eadec88..94fac841358 100644
--- a/openmc/cell.py
+++ b/openmc/cell.py
@@ -343,8 +343,7 @@ def bounding_box(self):
         if self.region is not None:
             return self.region.bounding_box
         else:
-            return BoundingBox(np.array([-np.inf, -np.inf, -np.inf]),
-                               np.array([np.inf, np.inf, np.inf]))
+            return BoundingBox.infinite()
 
     @property
     def num_instances(self):
diff --git a/openmc/region.py b/openmc/region.py
index d3c03b89837..f679129c1fc 100644
--- a/openmc/region.py
+++ b/openmc/region.py
@@ -18,6 +18,11 @@ class Region(ABC):
     respective classes are typically not instantiated directly but rather are
     created through operators of the Surface and Region classes.
 
+    Attributes
+    ----------
+    bounding_box : openmc.BoundingBox
+        Axis-aligned bounding box of the region
+
     """
     def __and__(self, other):
         return Intersection((self, other))
@@ -415,7 +420,7 @@ class Intersection(Region, MutableSequence):
     Attributes
     ----------
     bounding_box : openmc.BoundingBox
-        Lower-left and upper-right coordinates of an axis-aligned bounding box
+        Axis-aligned bounding box of the region
 
     """
 
@@ -503,7 +508,7 @@ class Union(Region, MutableSequence):
     Attributes
     ----------
     bounding_box : openmc.BoundingBox
-        Lower-left and upper-right coordinates of an axis-aligned bounding box
+        Axis-aligned bounding box of the region
 
     """
 
@@ -594,7 +599,7 @@ class Complement(Region):
     node : openmc.Region
         Regions to take the complement of
     bounding_box : openmc.BoundingBox
-        Lower-left and upper-right coordinates of an axis-aligned bounding box
+        Axis-aligned bounding box of the region
 
     """