diff --git a/pyPRMS/parameters/Parameter.py b/pyPRMS/parameters/Parameter.py
index 7c96bb0..b7cc1d2 100644
--- a/pyPRMS/parameters/Parameter.py
+++ b/pyPRMS/parameters/Parameter.py
@@ -407,11 +407,17 @@ def outliers(self) -> Outliers:
         values_under = 0
         values_over = 0
 
-        if self.meta.get('minimum', None) is not None:
-            values_under = np.count_nonzero(self.data_raw < self.meta.get('minimum'))   # type: ignore
+        minval = self.meta.get('minimum', None)
+        maxval = self.meta.get('maximum', None)
+
+        # Bounded parameters store a dimension name (e.g. 'nhru') as the limit,
+        # so skip the comparison when a bound is a string. check_values() does
+        # the same.
+        if minval is not None and not isinstance(minval, str):
+            values_under = np.count_nonzero(self.data_raw < minval)   # type: ignore
 
-        if self.meta.get('maximum', None) is not None:
-            values_over = np.count_nonzero(self.data_raw > self.meta.get('maximum'))   # type: ignore
+        if maxval is not None and not isinstance(maxval, str):
+            values_over = np.count_nonzero(self.data_raw > maxval)   # type: ignore
 
         return Outliers(self.__name, values_under, values_over)
 
diff --git a/tests/func/test_Parameter.py b/tests/func/test_Parameter.py
index 86e2dec..2b2f5e3 100644
--- a/tests/func/test_Parameter.py
+++ b/tests/func/test_Parameter.py
@@ -59,6 +59,22 @@ def test_create_parameter_adhoc(self):
         assert not aparam.is_seg_param()
         assert not aparam.is_poi_param()
 
+    def test_param_outliers_string_bound(self, metadata_instance):
+        """outliers() should not crash for a bounded parameter whose limit is a dimension name."""
+        # lake_hru_id is a bounded parameter: its maximum is the dimension name
+        # 'nlake', which can't be compared numerically against the int data.
+        global_dimensions = Dimensions(metadata=MetaData(verbose=False).metadata)
+        global_dimensions.add(name='nhru', size=3)
+
+        aparam = Parameter(name='lake_hru_id', meta=metadata_instance, global_dims=global_dimensions)
+        aparam.data = np.array([0, 1, 2], dtype=np.int32)
+
+        result = aparam.outliers()
+
+        # The string maximum is skipped; the numeric minimum still applies.
+        assert result.under == 0
+        assert result.over == 0
+
     def test_create_parameter_no_metadata_strict(self):
         """A new parameter with no supplied metadata should have an empty dictionary
         for metadata"""