diff --git a/include/openmc/settings.h b/include/openmc/settings.h
index cc3887f8f..2185a95c2 100644
--- a/include/openmc/settings.h
+++ b/include/openmc/settings.h
@@ -105,6 +105,7 @@ extern int trigger_batch_interval;   //!< Batch interval for triggers
 extern "C" int verbosity;                //!< How verbose to make output
 extern double weight_cutoff;         //!< Weight cutoff for Russian roulette
 extern double weight_survive;        //!< Survival weight after Russian roulette
+extern std::unordered_set<int32_t> distribcells; //!< Manually set distribcells
 } // namespace settings
 
 //==============================================================================
diff --git a/src/geometry_aux.cpp b/src/geometry_aux.cpp
index 9d3062901..a4252b746 100644
--- a/src/geometry_aux.cpp
+++ b/src/geometry_aux.cpp
@@ -315,8 +315,10 @@ prepare_distribcell()
 {
   write_message("Preparing distributed cell instances...", 5);
 
+  // start with any cells manually specified via the C++ API
+  std::unordered_set<int32_t> distribcells = settings::distribcells;
+
   // Find all cells listed in a DistribcellFilter or CellInstanceFilter
-  std::unordered_set<int32_t> distribcells;
   for (auto& filt : model::tally_filters) {
     auto* distrib_filt = dynamic_cast<DistribcellFilter*>(filt.get());
     auto* cell_inst_filt = dynamic_cast<CellInstanceFilter*>(filt.get());
diff --git a/src/settings.cpp b/src/settings.cpp
index 2617da978..9aa3063c9 100644
--- a/src/settings.cpp
+++ b/src/settings.cpp
@@ -114,6 +114,7 @@ int trigger_batch_interval {1};
 int verbosity {7};
 double weight_cutoff {0.25};
 double weight_survive {1.0};
+std::unordered_set<int32_t> distribcells;
 
 } // namespace settings