diff --git a/src/pdn/include/pdn/PdnGen.hh b/src/pdn/include/pdn/PdnGen.hh
index 3daa952a7b5..0989dc24298 100644
--- a/src/pdn/include/pdn/PdnGen.hh
+++ b/src/pdn/include/pdn/PdnGen.hh
@@ -72,15 +72,18 @@ class PdnGen
   void setCoreDomain(odb::dbNet* power,
                      odb::dbNet* switched_power,
                      odb::dbNet* ground,
-                     const std::vector<odb::dbNet*>& secondary);
+                     const std::vector<odb::dbNet*>& secondary_power,
+                     const std::vector<odb::dbNet*>& secondary_ground);
   void makeRegionVoltageDomain(const std::string& name,
                                odb::dbNet* power,
                                odb::dbNet* switched_power,
                                odb::dbNet* ground,
-                               const std::vector<odb::dbNet*>& secondary_nets,
+                               const std::vector<odb::dbNet*>& secondary_power,
+                               const std::vector<odb::dbNet*>& secondary_ground,
                                odb::dbRegion* region);
 
   // Grids
+  void run(bool trim, bool add_pins, const std::string& report_file);
   void buildGrids(bool trim);
   std::vector<Grid*> findGrid(const std::string& name) const;
   void makeCoreGrid(VoltageDomain* domain,
diff --git a/src/pdn/src/PdnGen.cc b/src/pdn/src/PdnGen.cc
index 6466e95a42b..351c07f3b2d 100644
--- a/src/pdn/src/PdnGen.cc
+++ b/src/pdn/src/PdnGen.cc
@@ -29,6 +29,7 @@
 #include "straps.h"
 #include "techlayer.h"
 #include "utl/Logger.h"
+#include "utl/timer.h"
 #include "via.h"
 #include "via_repair.h"
 
@@ -58,6 +59,14 @@ void PdnGen::resetShapes()
   updateRenderer();
 }
 
+void PdnGen::run(bool trim, bool add_pins, const std::string& report_file)
+{
+  utl::Timer timer;
+  buildGrids(trim);
+  writeToDb(add_pins, report_file);
+  logger_->info(utl::PDN, 500, "Runtime: {:.2f}s", timer.elapsed());
+}
+
 void PdnGen::buildGrids(bool trim)
 {
   debugPrint(logger_, utl::PDN, "Make", 1, "Build - begin");
@@ -254,7 +263,7 @@ VoltageDomain* PdnGen::getCoreDomain() const
 void PdnGen::ensureCoreDomain()
 {
   if (core_domain_ == nullptr) {
-    setCoreDomain(nullptr, nullptr, nullptr, {});
+    setCoreDomain(nullptr, nullptr, nullptr, {}, {});
   }
 }
 
@@ -291,14 +300,15 @@ VoltageDomain* PdnGen::findDomain(const std::string& name)
 void PdnGen::setCoreDomain(odb::dbNet* power,
                            odb::dbNet* switched_power,
                            odb::dbNet* ground,
-                           const std::vector<odb::dbNet*>& secondary)
+                           const std::vector<odb::dbNet*>& secondary_power,
+                           const std::vector<odb::dbNet*>& secondary_ground)
 {
   auto* block = db_->getChip()->getBlock();
   if (core_domain_ != nullptr) {
     logger_->warn(utl::PDN, 183, "Replacing existing core voltage domain.");
   }
   core_domain_ = std::make_unique<VoltageDomain>(
-      this, block, power, ground, secondary, logger_);
+      this, block, power, ground, secondary_power, secondary_ground, logger_);
 
   if (importUPF(core_domain_.get())) {
     if (switched_power) {
@@ -315,7 +325,8 @@ void PdnGen::makeRegionVoltageDomain(
     odb::dbNet* power,
     odb::dbNet* switched_power,
     odb::dbNet* ground,
-    const std::vector<odb::dbNet*>& secondary_nets,
+    const std::vector<odb::dbNet*>& secondary_power,
+    const std::vector<odb::dbNet*>& secondary_ground,
     odb::dbRegion* region)
 {
   if (region == nullptr) {
@@ -331,8 +342,15 @@ void PdnGen::makeRegionVoltageDomain(
     }
   }
   auto* block = db_->getChip()->getBlock();
-  auto domain = std::make_unique<VoltageDomain>(
-      this, name, block, power, ground, secondary_nets, region, logger_);
+  auto domain = std::make_unique<VoltageDomain>(this,
+                                                name,
+                                                block,
+                                                power,
+                                                ground,
+                                                secondary_power,
+                                                secondary_ground,
+                                                region,
+                                                logger_);
 
   if (importUPF(domain.get())) {
     if (switched_power) {
diff --git a/src/pdn/src/PdnGen.i b/src/pdn/src/PdnGen.i
index 4cefcd2f84f..a63f5d2dbe2 100644
--- a/src/pdn/src/PdnGen.i
+++ b/src/pdn/src/PdnGen.i
@@ -44,16 +44,29 @@ using utl::PDN;
 
 namespace pdn {
 
-void set_core_domain(odb::dbNet* power, odb::dbNet* switched_power, odb::dbNet* ground, const std::vector<odb::dbNet*>& secondary_nets)
+void set_core_domain(odb::dbNet* power,
+                     odb::dbNet* switched_power,
+                     odb::dbNet* ground,
+                     const std::vector<odb::dbNet*>& secondary_power,
+                     const std::vector<odb::dbNet*>& secondary_ground)
 {
   PdnGen* pdngen = ord::getPdnGen();
-  pdngen->setCoreDomain(power, switched_power, ground, secondary_nets);
+  pdngen->setCoreDomain(
+      power, switched_power, ground, secondary_power, secondary_ground);
 }
 
-void make_region_domain(const char* name, odb::dbNet* power, odb::dbNet* switched_power, odb::dbNet* ground, const std::vector<odb::dbNet*>& secondary_nets, odb::dbRegion* region)
+void make_region_domain(const char* name,
+                        odb::dbNet* power,
+                        odb::dbNet* switched_power,
+                        odb::dbNet* ground,
+                        const std::vector<odb::dbNet*>& secondary_power,
+                        const std::vector<odb::dbNet*>& secondary_ground,
+                        odb::dbRegion* region)
 {
   PdnGen* pdngen = ord::getPdnGen();
-  pdngen->makeRegionVoltageDomain(name, power, switched_power, ground, secondary_nets, region);
+  pdngen->makeRegionVoltageDomain(
+      name, power, switched_power, ground, secondary_power, secondary_ground,
+      region);
 }
 
 void reset()
@@ -68,6 +81,12 @@ void reset_shapes()
   pdngen->resetShapes();
 }
 
+void run_pdngen(bool trim, bool add_pins, const char* report_file)
+{
+  PdnGen* pdngen = ord::getPdnGen();
+  pdngen->run(trim, add_pins, report_file);
+}
+
 void build_grids(bool trim = true)
 {
   PdnGen* pdngen = ord::getPdnGen();
diff --git a/src/pdn/src/domain.cpp b/src/pdn/src/domain.cpp
index 17bbfa693c6..21a0f5467d0 100644
--- a/src/pdn/src/domain.cpp
+++ b/src/pdn/src/domain.cpp
@@ -18,11 +18,28 @@
 
 namespace pdn {
 
+namespace {
+void reportSecondaryNets(utl::Logger* logger,
+                         const char* label,
+                         const std::vector<odb::dbNet*>& nets)
+{
+  if (nets.empty()) {
+    return;
+  }
+  std::string names;
+  for (auto* net : nets) {
+    names += net->getName() + " ";
+  }
+  logger->report("  Secondary {} nets: {}", label, names);
+}
+}  // namespace
+
 VoltageDomain::VoltageDomain(PdnGen* pdngen,
                              odb::dbBlock* block,
                              odb::dbNet* power,
                              odb::dbNet* ground,
-                             const std::vector<odb::dbNet*>& secondary_nets,
+                             const std::vector<odb::dbNet*>& secondary_power,
+                             const std::vector<odb::dbNet*>& secondary_ground,
                              utl::Logger* logger)
     : name_("Core"),
       pdngen_(pdngen),
@@ -30,7 +47,8 @@ VoltageDomain::VoltageDomain(PdnGen* pdngen,
       power_(power),
       switched_power_(nullptr),
       ground_(ground),
-      secondary_(secondary_nets),
+      secondary_power_(secondary_power),
+      secondary_ground_(secondary_ground),
       region_(nullptr),
       logger_(logger)
 {
@@ -42,7 +60,8 @@ VoltageDomain::VoltageDomain(PdnGen* pdngen,
                              odb::dbBlock* block,
                              odb::dbNet* power,
                              odb::dbNet* ground,
-                             const std::vector<odb::dbNet*>& secondary_nets,
+                             const std::vector<odb::dbNet*>& secondary_power,
+                             const std::vector<odb::dbNet*>& secondary_ground,
                              odb::dbRegion* region,
                              utl::Logger* logger)
     : name_(name),
@@ -51,7 +70,8 @@ VoltageDomain::VoltageDomain(PdnGen* pdngen,
       power_(power),
       switched_power_(nullptr),
       ground_(ground),
-      secondary_(secondary_nets),
+      secondary_power_(secondary_power),
+      secondary_ground_(secondary_ground),
       region_(region),
       logger_(logger)
 {
@@ -75,21 +95,31 @@ std::vector<odb::dbNet*> VoltageDomain::getNets(bool start_with_power) const
   std::vector<odb::dbNet*> nets;
 
   if (start_with_power) {
+    // Order: primary power, switched power, secondary power nets,
+    //        secondary ground nets, primary ground.
+    // This groups all supply rails together before the ground rails,
+    // fixing the ordering issue for multi-rail designs (e.g., VDDA, VDD, VSS).
     nets.push_back(power_);
     if (switched_power_ != nullptr) {
       nets.push_back(switched_power_);
     }
+    nets.insert(nets.end(), secondary_power_.begin(), secondary_power_.end());
+    nets.insert(
+        nets.end(), secondary_ground_.begin(), secondary_ground_.end());
     nets.push_back(ground_);
   } else {
+    // Reverse order: primary ground, secondary ground nets,
+    //                secondary power nets, switched power, primary power.
     nets.push_back(ground_);
-    nets.push_back(power_);
+    nets.insert(
+        nets.end(), secondary_ground_.begin(), secondary_ground_.end());
+    nets.insert(nets.end(), secondary_power_.begin(), secondary_power_.end());
     if (switched_power_ != nullptr) {
       nets.push_back(switched_power_);
     }
+    nets.push_back(power_);
   }
 
-  nets.insert(nets.end(), secondary_.begin(), secondary_.end());
-
   return nets;
 }
 
@@ -210,13 +240,8 @@ void VoltageDomain::report() const
     logger_->report("  Switched power net: {}", switched_power_->getName());
   }
 
-  if (!secondary_.empty()) {
-    std::string nets;
-    for (auto* net : secondary_) {
-      nets += net->getName() + " ";
-    }
-    logger_->report("  Secondary nets: {}", nets);
-  }
+  reportSecondaryNets(logger_, "power", secondary_power_);
+  reportSecondaryNets(logger_, "ground", secondary_ground_);
 
   for (const auto& grid : grids_) {
     grid->report();
diff --git a/src/pdn/src/domain.h b/src/pdn/src/domain.h
index 39dc9572272..28c8ad5fbad 100644
--- a/src/pdn/src/domain.h
+++ b/src/pdn/src/domain.h
@@ -33,7 +33,8 @@ class VoltageDomain
                 odb::dbBlock* block,
                 odb::dbNet* power,
                 odb::dbNet* ground,
-                const std::vector<odb::dbNet*>& secondary_nets,
+                const std::vector<odb::dbNet*>& secondary_power,
+                const std::vector<odb::dbNet*>& secondary_ground,
                 odb::dbRegion* region,
                 utl::Logger* logger);
 
@@ -41,7 +42,8 @@ class VoltageDomain
                 odb::dbBlock* block,
                 odb::dbNet* power,
                 odb::dbNet* ground,
-                const std::vector<odb::dbNet*>& secondary_nets,
+                const std::vector<odb::dbNet*>& secondary_power,
+                const std::vector<odb::dbNet*>& secondary_ground,
                 utl::Logger* logger);  // Core
 
   const std::string& getName() const { return name_; }
@@ -54,6 +56,14 @@ class VoltageDomain
   odb::dbNet* getGround() const { return ground_; }
   odb::dbNet* getAlwaysOnPower() const { return power_; }
   odb::dbNet* getSwitchedPower() const { return switched_power_; }
+  const std::vector<odb::dbNet*>& getSecondaryPower() const
+  {
+    return secondary_power_;
+  }
+  const std::vector<odb::dbNet*>& getSecondaryGround() const
+  {
+    return secondary_ground_;
+  }
 
   void setSwitchedPower(odb::dbNet* switched_power)
   {
@@ -62,6 +72,9 @@ class VoltageDomain
   bool hasSwitchedPower() const { return switched_power_ != nullptr; }
 
   // returns the order in which the nets should be arranged in the grid shapes
+  // ordering: [power, switched_power?, ...secondary_power,
+  //            ...secondary_ground, ground] when start_with_power is true,
+  // and the reverse when false.
   std::vector<odb::dbNet*> getNets(bool start_with_power = true) const;
 
   bool hasRegion() const { return region_ != nullptr; }
@@ -90,7 +103,8 @@ class VoltageDomain
   odb::dbNet* power_;
   odb::dbNet* switched_power_;
   odb::dbNet* ground_;
-  std::vector<odb::dbNet*> secondary_;
+  std::vector<odb::dbNet*> secondary_power_;
+  std::vector<odb::dbNet*> secondary_ground_;
 
   odb::dbRegion* region_;
 
diff --git a/src/pdn/src/pdn.tcl b/src/pdn/src/pdn.tcl
index a58fcabc5e3..987b665acf3 100644
--- a/src/pdn/src/pdn.tcl
+++ b/src/pdn/src/pdn.tcl
@@ -1,6 +1,21 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright (c) 2022-2025, The OpenROAD Authors
 
+# Resolve a list of net name strings to dbNet objects.
+# Reports PDN error $err_id if any name is not found.
+proc pdn::collect_secondary_nets { net_names err_id type_label } {
+  set nets {}
+  foreach snet $net_names {
+    set db_net [[ord::get_db_block] findNet $snet]
+    if { $db_net == "NULL" } {
+      utl::error PDN $err_id "Unable to find secondary $type_label net: $snet"
+    } else {
+      lappend nets $db_net
+    }
+  }
+  return $nets
+}
+
 sta::define_cmd_args "pdngen" {[-skip_trim] \
                                [-dont_add_pins] \
                                [-reset] \
@@ -62,8 +77,7 @@ proc pdngen { args } {
   }
 
   pdn::check_setup
-  pdn::build_grids $trim
-  pdn::write_to_db $add_pins $failed_via_report
+  pdn::run_pdngen $trim $add_pins $failed_via_report
   pdn::reset_shapes
 }
 
@@ -71,12 +85,14 @@ sta::define_cmd_args "set_voltage_domain" {-name domain_name \
                                            -power power_net_name \
                                            -ground ground_net_name \
                                            [-region region_name] \
-                                           [-secondary_power secondary_power_net_name] \
+                                           [-secondary_power list_of_secondary_power_nets] \
+                                           [-secondary_ground list_of_secondary_ground_nets] \
                                            [-switched_power switched_power_net_name]}
 
 proc set_voltage_domain { args } {
   sta::parse_key_args "set_voltage_domain" args \
-    keys {-name -region -power -ground -secondary_power -switched_power} flags {}
+    keys {-name -region -power -ground -secondary_power -secondary_ground \
+          -switched_power} flags {}
 
   sta::check_argc_eq0 "set_voltage_domain" $args
 
@@ -115,16 +131,16 @@ proc set_voltage_domain { args } {
     }
   }
 
-  set secondary {}
+  set secondary_power {}
   if { [info exists keys(-secondary_power)] } {
-    foreach snet $keys(-secondary_power) {
-      set db_net [[ord::get_db_block] findNet $snet]
-      if { $db_net == "NULL" } {
-        utl::error PDN 1006 "Unable to find secondary power net: $snet"
-      } else {
-        lappend secondary $db_net
-      }
-    }
+    set secondary_power \
+        [pdn::collect_secondary_nets $keys(-secondary_power) 1006 "power"]
+  }
+
+  set secondary_ground {}
+  if { [info exists keys(-secondary_ground)] } {
+    set secondary_ground \
+        [pdn::collect_secondary_nets $keys(-secondary_ground) 1007 "ground"]
   }
 
   set switched_power "NULL"
@@ -148,9 +164,11 @@ proc set_voltage_domain { args } {
     if { [info exists keys(-name)] && [pdn::modify_voltage_domain_name $keys(-name)] != "Core" } {
       utl::warn PDN 1042 "Core voltage domain will be named \"Core\"."
     }
-    pdn::set_core_domain $pwr $switched_power $gnd $secondary
+    pdn::set_core_domain $pwr $switched_power $gnd $secondary_power \
+        $secondary_ground
   } else {
-    pdn::make_region_domain $name $pwr $switched_power $gnd $secondary $region
+    pdn::make_region_domain $name $pwr $switched_power $gnd $secondary_power \
+        $secondary_ground $region
   }
 }
 
diff --git a/src/pdn/test/core_grid_secondary_ground.tcl b/src/pdn/test/core_grid_secondary_ground.tcl
new file mode 100644
index 00000000000..696cf4da0e2
--- /dev/null
+++ b/src/pdn/test/core_grid_secondary_ground.tcl
@@ -0,0 +1,34 @@
+# Test that -secondary_ground nets are accepted and placed between the
+# secondary power nets and the primary ground net.
+# Strap group ordering for VDD / VDDA (secondary power) / VSSA (secondary
+# ground) / VSS must be: VDD, VDDA, VSSA, VSS.
+source "helpers.tcl"
+
+read_lef Nangate45/Nangate45.lef
+read_def nangate_gcd/floorplan.def
+
+add_global_connection -net VDD  -pin_pattern VDD  -power
+add_global_connection -net VSS  -pin_pattern VSS  -ground
+add_global_connection -net VDDA -pin_pattern VDDA -power
+add_global_connection -net VSSA -pin_pattern VSSA -ground
+
+set_voltage_domain -power VDD -ground VSS \
+    -secondary_power VDDA \
+    -secondary_ground VSSA
+
+define_pdn_grid -name "Core"
+add_pdn_stripe -followpins -layer metal1
+
+# All four nets participate in the metal4 straps.
+add_pdn_stripe -layer metal4 -width 0.48 -pitch 20.0 -offset 2.0
+add_pdn_stripe -layer metal7 -width 1.40 -pitch 40.0 -offset 2.0 \
+    -nets {VDD VSS}
+
+add_pdn_connect -layers {metal1 metal4}
+add_pdn_connect -layers {metal4 metal7}
+
+pdngen
+
+set def_file [make_result_file core_grid_secondary_ground.def]
+write_def $def_file
+diff_files core_grid_secondary_ground.defok $def_file
diff --git a/src/pdn/test/core_grid_secondary_power_ordering.tcl b/src/pdn/test/core_grid_secondary_power_ordering.tcl
new file mode 100644
index 00000000000..ccb77b07cf6
--- /dev/null
+++ b/src/pdn/test/core_grid_secondary_power_ordering.tcl
@@ -0,0 +1,32 @@
+# Test that secondary power nets are ordered between primary power and ground.
+# With -secondary_power VDDA, the strap group ordering must be:
+#   VDD (primary power), VDDA (secondary power), VSS (ground)
+# rather than the old broken ordering of VDD, VSS, VDDA.
+source "helpers.tcl"
+
+read_lef Nangate45/Nangate45.lef
+read_def nangate_gcd/floorplan.def
+
+add_global_connection -net VDD  -pin_pattern VDD  -power
+add_global_connection -net VSS  -pin_pattern VSS  -ground
+add_global_connection -net VDDA -pin_pattern VDDA -power
+
+set_voltage_domain -power VDD -ground VSS -secondary_power VDDA
+
+define_pdn_grid -name "Core"
+add_pdn_stripe -followpins -layer metal1
+
+# All three nets participate in the metal4 straps; ordering within each
+# pitch group must be VDD, VDDA, VSS (power rails first, ground last).
+add_pdn_stripe -layer metal4 -width 0.48 -pitch 15.0 -offset 2.0
+add_pdn_stripe -layer metal7 -width 1.40 -pitch 20.0 -offset 2.0 \
+    -nets {VDD VSS}
+
+add_pdn_connect -layers {metal1 metal4}
+add_pdn_connect -layers {metal4 metal7}
+
+pdngen
+
+set def_file [make_result_file core_grid_secondary_power_ordering.def]
+write_def $def_file
+diff_files core_grid_secondary_power_ordering.defok $def_file