diff --git a/lib/gpu/README b/lib/gpu/README
index b720aa65cb..7cc1aea8fb 100644
--- a/lib/gpu/README
+++ b/lib/gpu/README
@@ -136,10 +136,10 @@ IMPORTANT: If you re-build the library, e.g. for a different precision
 Makefile.linux clean, to ensure all previous derived files are removed
 before the new build is done.
 
-NOTE: The system-specific setting LAMMPS_SMALLBIG (default), LAMMPS_BIGBIG,
-      or LAMMPS_SMALLSMALL if specified when building LAMMPS (i.e. in
-      src/MAKE/Makefile.foo) should be consistent with that specified
-      when building libgpu.a (i.e. by LMP_INC in the lib/gpu/Makefile.bar).
+NOTE: The system-specific setting LAMMPS_SMALLBIG (default) or LAMMPS_BIGBIG
+      - if specified when building LAMMPS (i.e. in src/MAKE/Makefile.foo) -
+      should be consistent with that specified when building libgpu.a (i.e.
+      by LMP_INC in the lib/gpu/Makefile.bar).
 
 
 ------------------------------------------------------------------------------
diff --git a/tools/binary2txt.cpp b/tools/binary2txt.cpp
index 2369057324..2f7eb1e222 100644
--- a/tools/binary2txt.cpp
+++ b/tools/binary2txt.cpp
@@ -23,7 +23,7 @@
 #include <cstring>
 
 // these must match settings in src/lmptype.h which builds LAMMPS with
-//   -DLAMMPS_SMALLBIG (the default), -DLAMMPS_BIGBIG, or -DLAMMPS_SMALLSMALL
+//   -DLAMMPS_SMALLBIG (the default) or -DLAMMPS_BIGBIG
 // you can edit the tools/Makefile to enforce the same setting
 //   for the build of binary2txt, e.g.
 //   g++ -g -DLAMMPS_BIGBIG binarytxt.o -o binary2txt
@@ -36,7 +36,7 @@
 #define PRId64 "ld"
 #endif
 
-#if !defined(LAMMPS_SMALLSMALL) && !defined(LAMMPS_BIGBIG) && !defined(LAMMPS_SMALLBIG)
+#if !defined(LAMMPS_BIGBIG) && !defined(LAMMPS_SMALLBIG)
 #define LAMMPS_SMALLBIG
 #endif
 
@@ -44,10 +44,6 @@
 typedef int tagint;
 typedef int64_t bigint;
 #define BIGINT_FORMAT "%" PRId64
-#elif defined(LAMMPS_SMALLSMALL)
-typedef int tagint;
-typedef int bigint;
-#define BIGINT_FORMAT "%d"
 #else /* LAMMPS_BIGBIG */
 typedef int64_t tagint;
 typedef int64_t bigint;
diff --git a/unittest/c-library/test_library_external.cpp b/unittest/c-library/test_library_external.cpp
index 63ef4eee32..7783893931 100644
--- a/unittest/c-library/test_library_external.cpp
+++ b/unittest/c-library/test_library_external.cpp
@@ -14,10 +14,7 @@ using ::testing::HasSubstr;
 using ::testing::StartsWith;
 
 extern "C" {
-#ifdef LAMMPS_SMALLSMALL
-typedef int32_t step_t;
-typedef int32_t tag_t;
-#elif LAMMPS_SMALLBIG
+#if LAMMPS_SMALLBIG
 using step_t = int64_t;
 using tag_t  = int32_t;
 #else
diff --git a/unittest/c-library/test_library_properties.cpp b/unittest/c-library/test_library_properties.cpp
index 1feccf5cb0..3878b13774 100644
--- a/unittest/c-library/test_library_properties.cpp
+++ b/unittest/c-library/test_library_properties.cpp
@@ -127,15 +127,9 @@ TEST_F(LibraryProperties, thermo)
     const char *key = (const char *)lammps_last_thermo(lmp, "keyword", 0);
     EXPECT_THAT(key, StrEq("Step"));
     ival = *(int *)lammps_last_thermo(lmp, "type", 0);
-#if defined(LAMMPS_SMALLSMALL)
-    EXPECT_EQ(ival, LAMMPS_INT);
-    ival = *(int *)lammps_last_thermo(lmp, "data", 0);
-    EXPECT_EQ(ival, 2);
-#else
     EXPECT_EQ(ival, LAMMPS_INT64);
     bval = *(bigint *)lammps_last_thermo(lmp, "data", 0);
     EXPECT_EQ(bval, 2);
-#endif
 
     key = (const char *)lammps_last_thermo(lmp, "keyword", 1);
     EXPECT_THAT(key, StrEq("Temp"));
@@ -253,11 +247,7 @@ TEST_F(LibraryProperties, box)
 
 TEST_F(LibraryProperties, setting)
 {
-#if defined(LAMMPS_SMALLSMALL)
-    EXPECT_EQ(lammps_extract_setting(lmp, "bigint"), 4);
-#else
     EXPECT_EQ(lammps_extract_setting(lmp, "bigint"), 8);
-#endif
 #if defined(LAMMPS_BIGBIG)
     EXPECT_EQ(lammps_extract_setting(lmp, "tagint"), 8);
     EXPECT_EQ(lammps_extract_setting(lmp, "imageint"), 8);
@@ -375,15 +365,9 @@ TEST_F(LibraryProperties, global)
     char *c_ptr = (char *)lammps_extract_global(lmp, "units");
     EXPECT_THAT(c_ptr, StrEq("real"));
 
-#if defined(LAMMPS_SMALLSMALL)
-    EXPECT_EQ(lammps_extract_global_datatype(lmp, "ntimestep"), LAMMPS_INT);
-    int *i_ptr = (int *)lammps_extract_global(lmp, "ntimestep");
-    EXPECT_EQ((*i_ptr), 2);
-#else
     EXPECT_EQ(lammps_extract_global_datatype(lmp, "ntimestep"), LAMMPS_INT64);
     auto *b_ptr = (int64_t *)lammps_extract_global(lmp, "ntimestep");
     EXPECT_EQ((*b_ptr), 2);
-#endif
 
     EXPECT_EQ(lammps_extract_global_datatype(lmp, "dt"), LAMMPS_DOUBLE);
     auto *d_ptr = (double *)lammps_extract_global(lmp, "dt");
diff --git a/unittest/fortran/wrap_extract_global.cpp b/unittest/fortran/wrap_extract_global.cpp
index bf442279a1..eb47b00228 100644
--- a/unittest/fortran/wrap_extract_global.cpp
+++ b/unittest/fortran/wrap_extract_global.cpp
@@ -85,11 +85,7 @@ TEST_F(LAMMPS_extract_global, units)
 TEST_F(LAMMPS_extract_global, ntimestep)
 {
     f_lammps_setup_extract_global();
-#ifdef LAMMPS_SMALLSMALL
-    EXPECT_EQ(f_lammps_extract_global_ntimestep(), 0);
-#else
     EXPECT_EQ(f_lammps_extract_global_ntimestep_big(), 0l);
-#endif
 };
 
 TEST_F(LAMMPS_extract_global, dt)
@@ -134,17 +130,10 @@ TEST_F(LAMMPS_extract_global, boxprops)
 TEST_F(LAMMPS_extract_global, atomprops)
 {
     f_lammps_setup_extract_global();
-#ifdef LAMMPS_SMALLSMALL
-    EXPECT_EQ(f_lammps_extract_global_natoms(), 2);
-    EXPECT_EQ(f_lammps_extract_global_nbonds(), 0);
-    EXPECT_EQ(f_lammps_extract_global_nangles(), 0);
-    EXPECT_EQ(f_lammps_extract_global_ndihedrals(), 0);
-#else
     EXPECT_EQ(f_lammps_extract_global_natoms_big(), 2l);
     EXPECT_EQ(f_lammps_extract_global_nbonds_big(), 0l);
     EXPECT_EQ(f_lammps_extract_global_nangles_big(), 0l);
     EXPECT_EQ(f_lammps_extract_global_ndihedrals_big(), 0l);
-#endif
 
     EXPECT_EQ(f_lammps_extract_global_ntypes(), 1);
     EXPECT_EQ(f_lammps_extract_global_nlocal(), 2);
@@ -163,15 +152,8 @@ TEST_F(LAMMPS_extract_global, fullprops)
     if (!lammps_has_style(lmp, "atom", "full")) GTEST_SKIP();
     // This is not currently the world's most convincing test....
     f_lammps_setup_full_extract_global();
-#ifdef LAMMPS_SMALLSMALL
-    EXPECT_EQ(f_lammps_extract_global_natoms(), 2);
-    EXPECT_EQ(f_lammps_extract_global_nbonds(), 0);
-    EXPECT_EQ(f_lammps_extract_global_nangles(), 0);
-    EXPECT_EQ(f_lammps_extract_global_ndihedrals(), 0);
-#else
     EXPECT_EQ(f_lammps_extract_global_natoms_big(), 2l);
     EXPECT_EQ(f_lammps_extract_global_nbonds_big(), 0l);
     EXPECT_EQ(f_lammps_extract_global_nangles_big(), 0l);
     EXPECT_EQ(f_lammps_extract_global_ndihedrals_big(), 0l);
-#endif
 }
diff --git a/unittest/fortran/wrap_get_thermo.cpp b/unittest/fortran/wrap_get_thermo.cpp
index 3a2b810858..7ad4319719 100644
--- a/unittest/fortran/wrap_get_thermo.cpp
+++ b/unittest/fortran/wrap_get_thermo.cpp
@@ -98,11 +98,7 @@ TEST_F(LAMMPS_thermo, last_thermo)
     thermostr = (char *)f_lammps_last_thermo_string(6);
     EXPECT_STREQ(thermostr, "Press");
     free(thermostr);
-#if defined(LAMMPS_SMALLSMALL)
-    EXPECT_EQ(f_lammps_last_thermo_type(1), multitype::LAMMPS_INT);
-#else
     EXPECT_EQ(f_lammps_last_thermo_type(1), multitype::LAMMPS_INT64);
-#endif
     EXPECT_EQ(f_lammps_last_thermo_int(1), 15);
     EXPECT_EQ(f_lammps_last_thermo_type(2), multitype::LAMMPS_DOUBLE);
     EXPECT_EQ(f_lammps_last_thermo_type(3), multitype::LAMMPS_DOUBLE);
diff --git a/unittest/fortran/wrap_properties.cpp b/unittest/fortran/wrap_properties.cpp
index 49ec134742..7478337fb1 100644
--- a/unittest/fortran/wrap_properties.cpp
+++ b/unittest/fortran/wrap_properties.cpp
@@ -77,11 +77,7 @@ TEST_F(LAMMPS_properties, get_mpi_comm)
 
 TEST_F(LAMMPS_properties, extract_setting)
 {
-#if defined(LAMMPS_SMALLSMALL)
-    EXPECT_EQ(f_lammps_extract_setting("bigint"), 4);
-#else
     EXPECT_EQ(f_lammps_extract_setting("bigint"), 8);
-#endif
 #if defined(LAMMPS_BIGBIG)
     EXPECT_EQ(f_lammps_extract_setting("tagint"), 8);
     EXPECT_EQ(f_lammps_extract_setting("imageint"), 8);
diff --git a/unittest/utils/test_lmptype.cpp b/unittest/utils/test_lmptype.cpp
index a14f3a2cab..96b1c89c31 100644
--- a/unittest/utils/test_lmptype.cpp
+++ b/unittest/utils/test_lmptype.cpp
@@ -25,11 +25,7 @@ TEST(Types, ubuf)
     double buf[3];
     double d1 = 0.1;
     int i1    = -10;
-#if defined(LAMMPS_SMALLSMALL)
-    bigint b1 = 2048;
-#else
     bigint b1 = (1L << 58) + (1L << 50);
-#endif
     buf[0] = d1;
     buf[1] = ubuf(i1).d;
     buf[2] = ubuf(b1).d;
@@ -58,11 +54,7 @@ TEST(Types, multitype)
     EXPECT_EQ(m[1].type, multitype::LAMMPS_INT);
     EXPECT_EQ(m[2].type, multitype::LAMMPS_DOUBLE);
 
-#if defined(LAMMPS_SMALLSMALL)
-    EXPECT_EQ(m[3].type, multitype::LAMMPS_INT);
-#else
     EXPECT_EQ(m[3].type, multitype::LAMMPS_INT64);
-#endif
     EXPECT_EQ(m[4].type, multitype::LAMMPS_INT);
     EXPECT_EQ(m[5].type, multitype::LAMMPS_DOUBLE);
     EXPECT_EQ(m[6].type, multitype::LAMMPS_NONE);
@@ -71,9 +63,7 @@ TEST(Types, multitype)
     EXPECT_EQ(m[1].data.i, i1);
     EXPECT_EQ(m[2].data.d, d1);
 
-#if !defined(LAMMPS_SMALLSMALL)
     EXPECT_EQ(m[3].data.b, -((1L << 40) + (1L << 50)));
-#endif
     EXPECT_EQ(m[4].data.i, -1023);
     EXPECT_EQ(m[5].data.d, -2.225);
 }