diff --git a/coupled_AM2_LM3_SIS2/Makefile b/coupled_AM2_LM3_SIS2/Makefile
index 3ceca25666..3f9d7ace0b 100644
--- a/coupled_AM2_LM3_SIS2/Makefile
+++ b/coupled_AM2_LM3_SIS2/Makefile
@@ -37,7 +37,7 @@ EXCLUDE ?= \
 # Autoconf setup
 EXTRA_SRC_DIRS = \
   $(abspath ../src/SIS2/src) \
-  $(abspath ../src/SIS2/config_src/external) \
+  $(abspath ../src/SIS2/config_src/external/Icepack_interfaces) \
   $(abspath ../src/coupler)
 
 CONFIG_FLAGS := --config-cache
diff --git a/ice_ocean_SIS2/Makefile b/ice_ocean_SIS2/Makefile
index eee1a4b38d..786613e659 100644
--- a/ice_ocean_SIS2/Makefile
+++ b/ice_ocean_SIS2/Makefile
@@ -38,7 +38,7 @@ EXCLUDE ?= \
 # Autoconf setup
 EXTRA_SRC_DIRS := \
   $(abspath ../src/SIS2/src) \
-  $(abspath ../src/SIS2/config_src/external) \
+  $(abspath ../src/SIS2/config_src/external/Icepack_interfaces) \
   $(abspath $(dir $(wildcard ../src/coupler/full/ice_ocean_flux_exchange.F90)) \
             $(dir $(wildcard ../src/coupler/shared/surface_flux.F90)) \
             $(dir $(wildcard ../src/coupler/surface_flux.F90)) )
diff --git a/tools/MRS/Makefile.build b/tools/MRS/Makefile.build
index 22bdcbceaa..59d9427154 100644
--- a/tools/MRS/Makefile.build
+++ b/tools/MRS/Makefile.build
@@ -186,10 +186,30 @@ $(eval $(call compile,,MOM6,$$(ENV_SCRIPT),))
 # Generate lists of variables and dependencies for SIS2 libraries
 # $(1) = compiler, $(2) = mode, $(3) = memory style, $(4) = mom6 configuration
 define sis2-variables
-$(BUILD)/$(1)/$(2)/dynamic_nonsymmetric/$(4)/path_names: $(SIS2_SRC)/config_src/dynamic/* $(SIS2_SRC)/config_src/external/* $(SIS2_SRC)/src/* $(MOM6_SRC)/src/framework/MOM_memory_macros.h
-$(BUILD)/$(1)/$(2)/dynamic_nonsymmetric/$(4)/path_names: LIST_PATHS_ARGS =  $(SIS2_SRC)/config_src/dynamic/ $(SIS2_SRC)/config_src/external/* $(SIS2_SRC)/src/ $(MOM6_SRC)/src/framework/MOM_memory_macros.h
-$(BUILD)/$(1)/$(2)/dynamic_symmetric/$(4)/path_names: $(SIS2_SRC)/config_src/dynamic_symmetric/* $(SIS2_SRC)/config_src/external/* $(SIS2_SRC)/src/* $(MOM6_SRC)/src/framework/MOM_memory_macros.h
-$(BUILD)/$(1)/$(2)/dynamic_symmetric/$(4)/path_names: LIST_PATHS_ARGS =  $(SIS2_SRC)/config_src/dynamic_symmetric/ $(SIS2_SRC)/config_src/external/* $(SIS2_SRC)/src/ $(MOM6_SRC)/src/framework/MOM_memory_macros.h
+$(BUILD)/$(1)/$(2)/dynamic_nonsymmetric/$(4)/path_names: \
+  $(SIS2_SRC)/config_src/dynamic/* \
+  $(SIS2_SRC)/config_src/external/Icepack_interfaces/* \
+  $(SIS2_SRC)/src/* \
+  $(MOM6_SRC)/src/framework/MOM_memory_macros.h
+
+$(BUILD)/$(1)/$(2)/dynamic_nonsymmetric/$(4)/path_names: \
+  LIST_PATHS_ARGS = $(SIS2_SRC)/config_src/dynamic/ \
+  $(SIS2_SRC)/config_src/external/Icepack_interfaces/ \
+  $(SIS2_SRC)/src/ \
+  $(MOM6_SRC)/src/framework/MOM_memory_macros.h
+
+$(BUILD)/$(1)/$(2)/dynamic_symmetric/$(4)/path_names: \
+  $(SIS2_SRC)/config_src/dynamic_symmetric/* \
+  $(SIS2_SRC)/config_src/external/Icepack_interfaces/* \
+  $(SIS2_SRC)/src/* \
+  $(MOM6_SRC)/src/framework/MOM_memory_macros.h
+
+$(BUILD)/$(1)/$(2)/dynamic_symmetric/$(4)/path_names: \
+  LIST_PATHS_ARGS = $(SIS2_SRC)/config_src/dynamic_symmetric/ \
+  $(SIS2_SRC)/config_src/external/Icepack_interfaces/ \
+  $(SIS2_SRC)/src/ \
+  $(MOM6_SRC)/src/framework/MOM_memory_macros.h
+
 $(BUILD)/$(1)/$(2)/$(3)/$(4)/Makefile: CPP_DEFS = -D_FILE_VERSION="`$(GIT_VERSION_SCRIPT) $$$$<`" -DSTATSLABEL=\"$(STATS_PLATFORM)$(1)$(STATS_COMPILER_VER)\"
 $(BUILD)/$(1)/$(2)/$(3)/$(4)/libsis2.a: $(BUILD)/$(1)/$(2)/icebergs/libicebergs.a $(BUILD)/$(1)/$(2)/ice_param/libice_param.a
 .SECONDARY: $(BUILD)/$(1)/$(2)/$(3)/$(4)/path_names