diff --git a/src/common/quantile.h b/src/common/quantile.h
index acaf0b225c15..07e573bfb206 100644
--- a/src/common/quantile.h
+++ b/src/common/quantile.h
@@ -720,6 +720,8 @@ class HostSketchContainer {
 
   static uint32_t SearchGroupIndFromRow(std::vector<bst_uint> const &group_ptr,
                                         size_t const base_rowid) {
+    CHECK_LT(base_rowid, group_ptr.back())
+        << "Row: " << base_rowid << " is not found in any group.";
     bst_group_t group_ind =
         std::upper_bound(group_ptr.cbegin(), group_ptr.cend() - 1, base_rowid) -
         group_ptr.cbegin() - 1;