diff --git a/cime_config/config_grids.xml b/cime_config/config_grids.xml
index 6c478c23541a..5b1a247deedc 100755
--- a/cime_config/config_grids.xml
+++ b/cime_config/config_grids.xml
@@ -721,6 +721,16 @@
       <mask>oEC60to30v3</mask>
     </model_grid>
 
+    <model_grid alias="r025_r025" compset="(DOCN|XOCN|SOCN|AQP1)">
+      <grid name="atm">r025</grid>
+      <grid name="lnd">r025</grid>
+      <grid name="ocnice">r025</grid>
+      <grid name="rof">r025</grid>
+      <grid name="glc">null</grid>
+      <grid name="wav">null</grid>
+      <mask>oEC60to30v3</mask>
+    </model_grid>
+
     <model_grid alias="r0125_r0125" compset="(DOCN|XOCN|SOCN|AQP1)">
       <grid name="atm">r0125</grid>
       <grid name="lnd">r0125</grid>
@@ -751,6 +761,16 @@
       <mask>oRRS18to6v3</mask>
     </model_grid>
 
+    <model_grid alias="r025_IcoswISC30E3r5" compset="(DATM.+ELM)">
+      <grid name="atm">r025</grid>
+      <grid name="lnd">r025</grid>
+      <grid name="ocnice">IcoswISC30E3r5</grid>
+      <grid name="rof">null</grid>
+      <grid name="glc">null</grid>
+      <grid name="wav">null</grid>
+      <mask>IcoswISC30E3r5</mask>
+    </model_grid>
+
     <!--  spectral element grids -->
 
     <model_grid alias="ne4_oQU480">
@@ -1426,6 +1446,26 @@
       <mask>oRRS18to6v3</mask>
     </model_grid>
 
+    <model_grid alias="ne120pg2_r025_IcoswISC30E3r5">
+      <grid name="atm">ne120np4.pg2</grid>
+      <grid name="lnd">r025</grid>
+      <grid name="ocnice">IcoswISC30E3r5</grid>
+      <grid name="rof">null</grid>
+      <grid name="glc">null</grid>
+      <grid name="wav">null</grid>
+      <mask>IcoswISC30E3r5</mask>
+    </model_grid>
+
+    <model_grid alias="ne30pg2_r025_IcoswISC30E3r5">
+      <grid name="atm">ne30np4.pg2</grid>
+      <grid name="lnd">r025</grid>
+      <grid name="ocnice">IcoswISC30E3r5</grid>
+      <grid name="rof">null</grid>
+      <grid name="glc">null</grid>
+      <grid name="wav">null</grid>
+      <mask>IcoswISC30E3r5</mask>
+    </model_grid>
+
     <model_grid alias="ne60_ne60" compset="(DOCN|XOCN|SOCN|AQP1)">
       <grid name="atm">ne60np4</grid>
       <grid name="lnd">ne60np4</grid>
@@ -2938,6 +2978,12 @@
       <desc>r0125 is 1/8 degree river routing grid:</desc>
     </domain>
 
+    <domain name="r025">
+      <nx>1440</nx>
+      <ny>720</ny>
+      <file grid="atm|lnd" mask="IcoswISC30E3r5">$DIN_LOC_ROOT/share/domains/domain.lnd.r025_IcoswISC30E3r5.240129.nc</file>
+    </domain>
+
     <domain name="mp120v1">
       <nx>28993</nx>
       <ny>1</ny>
@@ -3549,6 +3595,22 @@
       <map name="ATM2ROF_SMAPNAME">cpl/gridmaps/ne120pg2/map_ne120pg2_to_r0125_mono.200707.nc</map>
     </gridmap>
 
+    <gridmap atm_grid="ne120np4.pg2" lnd_grid="r025">
+      <map name="ATM2LND_FMAPNAME">cpl/gridmaps/ne120pg2/map_ne120pg2_to_r025_traave.20240206.nc</map>
+      <map name="ATM2LND_FMAPNAME_NONLINEAR">cpl/gridmaps/ne120pg2/map_ne120pg2_to_r025_trfv2.20240206.nc</map>
+      <map name="ATM2LND_SMAPNAME">cpl/gridmaps/ne120pg2/map_ne120pg2_to_r025_esmfbilin.20240206.nc</map>
+      <map name="LND2ATM_FMAPNAME">cpl/gridmaps/ne120pg2/map_r025_to_ne120pg2_traave.20240206.nc</map>
+      <map name="LND2ATM_SMAPNAME">cpl/gridmaps/ne120pg2/map_r025_to_ne120pg2_traave.20240206.nc</map>
+    </gridmap>
+
+    <gridmap atm_grid="ne30np4.pg2" lnd_grid="r025">
+      <map name="ATM2LND_FMAPNAME">cpl/gridmaps/ne120pg2/map_ne30pg2_to_r025_traave.20240206.nc</map>
+      <map name="ATM2LND_FMAPNAME_NONLINEAR">cpl/gridmaps/ne120pg2/map_ne30pg2_to_r025_trfv2.20240206.nc</map>
+      <map name="ATM2LND_SMAPNAME">cpl/gridmaps/ne120pg2/map_ne30pg2_to_r025_esmfbilin.20240206.nc</map>
+      <map name="LND2ATM_FMAPNAME">cpl/gridmaps/ne120pg2/map_r025_to_ne30pg2_traave.20240206.nc</map>
+      <map name="LND2ATM_SMAPNAME">cpl/gridmaps/ne120pg2/map_r025_to_ne30pg2_traave.20240206.nc</map>
+    </gridmap>
+
     <gridmap atm_grid="ne120np4" ocn_grid="oRRS18to6v3">
       <map name="ATM2OCN_FMAPNAME">cpl/gridmaps/ne120np4/map_ne120np4_to_oRRS18to6v3_mono.20200702.nc</map>
       <map name="ATM2OCN_VMAPNAME">cpl/gridmaps/ne120np4/map_ne120np4_to_oRRS18to6v3_mono.20200702.nc</map>
diff --git a/components/elm/bld/namelist_files/namelist_defaults.xml b/components/elm/bld/namelist_files/namelist_defaults.xml
index 1206505b5a0a..356e5be3cdc0 100644
--- a/components/elm/bld/namelist_files/namelist_defaults.xml
+++ b/components/elm/bld/namelist_files/namelist_defaults.xml
@@ -305,6 +305,8 @@ lnd/clm2/surfdata_map/surfdata_ne256pg2_simyr2010_c230207.nc</fsurdat>
 lnd/clm2/surfdata_map/surfdata_ne1024pg2_simyr2010_c211021.nc</fsurdat>
 <fsurdat hgrid="ne1024np4"   sim_year="2010" use_crop=".false." >
 lnd/clm2/surfdata_map/surfdata_ne1024np4_simyr2010_c220523.nc</fsurdat>
+<fsurdat hgrid="r025"   sim_year="2010" use_crop=".false." >
+lnd/clm2/surfdata_map/surfdata_0.25x0.25_simyr2010_c240206_TOP.nc</fsurdat>
 
 <!-- for present day simulations - year 2000 -->
 <fsurdat hgrid="360x720cru"   sim_year="2000" use_crop=".false." >
@@ -441,6 +443,8 @@ lnd/clm2/surfdata_map/surfdata_0.5x0.5_simyr1850_c211019.nc</fsurdat>
 lnd/clm2/surfdata_map/surfdata_0.125x0.125_simyr1850_c190730.nc</fsurdat>
 <fsurdat hgrid="r0125"        sim_year="1950" use_crop=".false." >
 lnd/clm2/surfdata_map/surfdata_0.125x0.125_simyr1950_c210924.nc</fsurdat>
+<fsurdat hgrid="r025"    sim_year="1850" use_crop=".false." >
+lnd/clm2/surfdata_map/surfdata_0.25x0.25_simyr1850_c240125_TOP.nc</fsurdat>
 
 <fsurdat hgrid="ne0np4_conus_x4v1_lowcon" sim_year="1850" use_crop=".false." >
 lnd/clm2/surfdata_map/surfdata_conusx4v1_simyr1850_c160503.nc</fsurdat>
@@ -2073,6 +2077,39 @@ this mask will have smb calculated over the entire global land surface
 
 <!-- mapping files for r0125xr0125 END -->
 
+<map frm_hgrid="0.5x0.5"    frm_lmask="AVHRR"  to_hgrid="r025xr025"   to_lmask="nomask"
+>lnd/clm2/mappingdata/maps/0.25x0.25/map_0.5x0.5_AVHRR_to_0.25x0.25_nomask_aave_da_c240123.nc</map>
+<map frm_hgrid="0.5x0.5"    frm_lmask="MODIS"  to_hgrid="r025xr025"   to_lmask="nomask"
+>lnd/clm2/mappingdata/maps/0.25x0.25/map_0.5x0.5_MODIS_to_0.25x0.25_nomask_aave_da_c240123.nc</map>
+<map frm_hgrid="0.9x1.25"    frm_lmask="GRDC"  to_hgrid="r025xr025"   to_lmask="nomask"
+>lnd/clm2/mappingdata/maps/0.25x0.25/map_0.9x1.25_GRDC_to_0.25x0.25_nomask_aave_da_c240124.nc</map>
+<map frm_hgrid="10x10min"    frm_lmask="IGBPmergeICESatGIS"  to_hgrid="r025xr025"   to_lmask="nomask"
+>lnd/clm2/mappingdata/maps/0.25x0.25/map_10x10min_IGBPmergeICESatGIS_to_0.25x0.25_nomask_aave_da_c240123.nc</map>
+<map frm_hgrid="10x10min"    frm_lmask="nomask"  to_hgrid="r025xr025"   to_lmask="nomask"
+>lnd/clm2/mappingdata/maps/0.25x0.25/map_10x10min_nomask_to_0.25x0.25_nomask_aave_da_c240123.nc</map>
+<map frm_hgrid="1km-merge-10min"    frm_lmask="HYDRO1K-merge-nomask"  to_hgrid="r025xr025"   to_lmask="nomask"
+>lnd/clm2/mappingdata/maps/0.25x0.25/map_1km-merge-10min_HYDRO1K-merge-nomask_to_0.25x0.25_nomask_aave_da_c240123.nc</map>
+<map frm_hgrid="360x720cru"    frm_lmask="cruncep"  to_hgrid="r025xr025"   to_lmask="nomask"
+>lnd/clm2/mappingdata/maps/0.25x0.25/map_360x720cru_cruncep_to_0.25x0.25_nomask_aave_da_c240124.nc</map>
+<map frm_hgrid="3x3min"    frm_lmask="GLOBE-Gardner-mergeGIS"  to_hgrid="r025xr025"   to_lmask="nomask"
+>lnd/clm2/mappingdata/maps/0.25x0.25/map_3x3min_GLOBE-Gardner-mergeGIS_to_0.25x0.25_nomask_aave_da_c240123.nc</map>
+<map frm_hgrid="3x3min"    frm_lmask="GLOBE-Gardner"  to_hgrid="r025xr025"   to_lmask="nomask"
+>lnd/clm2/mappingdata/maps/0.25x0.25/map_3x3min_GLOBE-Gardner_to_0.25x0.25_nomask_aave_da_c240123.nc</map>
+<map frm_hgrid="3x3min"    frm_lmask="LandScan2004"  to_hgrid="r025xr025"   to_lmask="nomask"
+>lnd/clm2/mappingdata/maps/0.25x0.25/map_3x3min_LandScan2004_to_0.25x0.25_nomask_aave_da_c240123.nc</map>
+<map frm_hgrid="3x3min"    frm_lmask="MODIS"  to_hgrid="r025xr025"   to_lmask="nomask"
+>lnd/clm2/mappingdata/maps/0.25x0.25/map_3x3min_MODIS_to_0.25x0.25_nomask_aave_da_c240123.nc</map>
+<map frm_hgrid="3x3min"    frm_lmask="USGS"  to_hgrid="r025xr025"   to_lmask="nomask"
+>lnd/clm2/mappingdata/maps/0.25x0.25/map_3x3min_USGS_to_0.25x0.25_nomask_aave_da_c240123.nc</map>
+<map frm_hgrid="5x5min"    frm_lmask="IGBP-GSDP"  to_hgrid="r025xr025"   to_lmask="nomask"
+>lnd/clm2/mappingdata/maps/0.25x0.25/map_5x5min_IGBP-GSDP_to_0.25x0.25_nomask_aave_da_c240123.nc</map>
+<map frm_hgrid="5x5min"    frm_lmask="ISRIC-WISE"  to_hgrid="r025xr025"   to_lmask="nomask"
+>lnd/clm2/mappingdata/maps/0.25x0.25/map_5x5min_ISRIC-WISE_to_0.25x0.25_nomask_aave_da_c240123.nc</map>
+<map frm_hgrid="5x5min"    frm_lmask="nomask"  to_hgrid="r025xr025"   to_lmask="nomask"
+>lnd/clm2/mappingdata/maps/0.25x0.25/map_5x5min_nomask_to_0.25x0.25_nomask_aave_da_c240123.nc</map>
+<map frm_hgrid="0.5x0.5"    frm_lmask="GSDTG2000"  to_hgrid="r025xr025"   to_lmask="nomask"
+>lnd/clm2/mappingdata/maps/0.25x0.25/map_0.5x0.5_GSDTG2000_to_0.25x0.25_nomask_aave_da_c240123.nc</map>
+
 <map frm_hgrid="0.5x0.5"    frm_lmask="AVHRR"  to_hgrid="ne0np4_antarcticax4v1"   to_lmask="nomask"
 >lnd/clm2/mappingdata/maps/antarcticax4v1/map_0.5x0.5_AVHRR_to_antarcticax4v1_nomask_aave_da_c210130.nc</map>
 <map frm_hgrid="0.5x0.5"    frm_lmask="MODIS"  to_hgrid="ne0np4_antarcticax4v1"   to_lmask="nomask"
diff --git a/components/elm/bld/namelist_files/namelist_definition.xml b/components/elm/bld/namelist_files/namelist_definition.xml
index c08951338d74..55abc0ef3069 100644
--- a/components/elm/bld/namelist_files/namelist_definition.xml
+++ b/components/elm/bld/namelist_files/namelist_definition.xml
@@ -1410,7 +1410,7 @@ CLM run type.
 <entry id="res" type="char*30" category="default_settings"
        group="default_settings"
        valid_values=
-"512x1024,360x720cru,128x256,64x128,48x96,32x64,8x16,94x192,0.23x0.31,0.9x1.25,1.9x2.5,2.5x3.33,4x5,10x15,5x5_amazon,1x1_tropicAtl,1x1_camdenNJ,1x1_vancouverCAN,1x1_mexicocityMEX,1x1_asphaltjungleNJ,1x1_brazil,1x1_urbanc_alpha,1x1_numaIA,1x1_smallvilleIA,0.1x0.1,0.5x0.5,3x3min,5x5min,10x10min,0.33x0.33,ne4np4,ne4np4.pg2,ne11np4,ne16np4,ne30np4,ne30np4.pg2,ne60np4,ne120np4,ne120np4.pg2,ne240np4,ne256np4,ne256np4.pg2,ne1024np4,ne1024np4.pg2,1km-merge-10min,ne0np4_arm_x8v3_lowcon,ne0np4_conus_x4v1_lowcon,ne0np4_enax4v1,ne0np4_twpx4v1,r2,r05,r0125,NLDAS,ne0np4_northamericax4v1.pg2,ne0np4_arcticx4v1.pg2">
+"512x1024,360x720cru,128x256,64x128,48x96,32x64,8x16,94x192,0.23x0.31,0.9x1.25,1.9x2.5,2.5x3.33,4x5,10x15,5x5_amazon,1x1_tropicAtl,1x1_camdenNJ,1x1_vancouverCAN,1x1_mexicocityMEX,1x1_asphaltjungleNJ,1x1_brazil,1x1_urbanc_alpha,1x1_numaIA,1x1_smallvilleIA,0.1x0.1,0.5x0.5,3x3min,5x5min,10x10min,0.33x0.33,ne4np4,ne4np4.pg2,ne11np4,ne16np4,ne30np4,ne30np4.pg2,ne60np4,ne120np4,ne120np4.pg2,ne240np4,ne256np4,ne256np4.pg2,ne1024np4,ne1024np4.pg2,1km-merge-10min,ne0np4_arm_x8v3_lowcon,ne0np4_conus_x4v1_lowcon,ne0np4_enax4v1,ne0np4_twpx4v1,r2,r05,r0125,NLDAS,ne0np4_northamericax4v1.pg2,ne0np4_arcticx4v1.pg2,r025">
 Horizontal resolutions
 Note: 0.1x0.1, 0.5x0.5, 5x5min, 10x10min, 3x3min and 0.33x0.33 are only used for CLM tools
 </entry>
diff --git a/components/elm/cime_config/config_compsets.xml b/components/elm/cime_config/config_compsets.xml
index 01366aa71dd9..a473f2b4fed9 100644
--- a/components/elm/cime_config/config_compsets.xml
+++ b/components/elm/cime_config/config_compsets.xml
@@ -129,6 +129,11 @@
     <lname>1850_DATM%QIA_ELM%CNPRDCTCBC_SICE_SOCN_MOSART_SGLC_SWAV</lname>
   </compset>
 
+  <compset>
+    <alias>I1850CNPRDCTCBCTOP</alias>
+    <lname>1850_DATM%QIA_ELM%CNPRDCTCBCTOP_SICE_SOCN_MOSART_SGLC_SWAV</lname>
+  </compset>
+
   <compset>
     <alias>ICB1850CRDCTCBC</alias>
     <lname>1850_SATM_ELM%CRDCTCBC_SICE_SOCN_MOSART_SGLC_SWAV</lname>
diff --git a/components/mosart/bld/namelist_files/namelist_defaults_mosart.xml b/components/mosart/bld/namelist_files/namelist_defaults_mosart.xml
index 9a7c5e4eeaed..1f7e44722127 100644
--- a/components/mosart/bld/namelist_files/namelist_defaults_mosart.xml
+++ b/components/mosart/bld/namelist_files/namelist_defaults_mosart.xml
@@ -42,12 +42,14 @@ for the CLM data in the CESM distribution
 <!-- River Transport Model river routing file (relative to {csmdata}) -->
 
 <frivinp_rtm rof_grid="r0125" >rof/mosart/MOSART_global_8th_20180211c.nc</frivinp_rtm>
+<frivinp_rtm rof_grid="r025" >rof/mosart/MOSART_global_qd_20240212.v3.nc</frivinp_rtm>
 <frivinp_rtm rof_grid="r05" >rof/mosart/MOSART_global_half_20180721a.nc</frivinp_rtm>
 <frivinp_rtm rof_grid="r2" >rof/mosart/MOSART_Global_2deg_antarctica_flowing_to_north_c09162020.nc</frivinp_rtm>
 <frivinp_rtm rof_grid="NLDAS" >rof/mosart/MOSART_NLDAS_8th_20160426.nc</frivinp_rtm>
 
 <!-- River Transport Model mesh file (relative to DIN_LOC_ROOT) -->
 <frivinp_mesh rof_grid="r0125" >share/meshes/rof/MOSART_global_8th.scrip.20180211c.nc</frivinp_mesh>
+<frivinp_mesh rof_grid="r025" >share/meshes/rof/SCRIPgrid_0.25x0.25_nomask_c200309.nc</frivinp_mesh>
 <frivinp_mesh rof_grid="r05" >share/meshes/rof/SCRIPgrid_0.5x0.5_nomask_c110308.nc</frivinp_mesh>
 <frivinp_mesh rof_grid="r2" >share/meshes/rof/SCRIPgrid_2x2_nomask_c210211.nc</frivinp_mesh>
 
diff --git a/components/mosart/cime_config/buildnml b/components/mosart/cime_config/buildnml
index ba015b01f6a0..90b3b3bb379a 100755
--- a/components/mosart/cime_config/buildnml
+++ b/components/mosart/cime_config/buildnml
@@ -46,8 +46,8 @@ def buildnml(case, caseroot, compname):
     # Verify rof grid is supported
     #--------------------------------------------------------------------
 
-    rof_grid_supported = ("null", "r2", "r05", "r0125", "r01", "NLDAS", "ELM_USRDAT")
-    expect(rof_grid in rof_grid_supported, "ROF_GRID '{}' is not supported in mosart. Choose from: null, r2, r05, r0125, r01, NLDAS, ELM_USRDAT".format(rof_grid))
+    rof_grid_supported = ("null", "r2", "r05", "r025", "r0125", "r01", "NLDAS", "ELM_USRDAT")
+    expect(rof_grid in rof_grid_supported, "ROF_GRID '{}' is not supported in mosart. Choose from: null, r2, r05, r025, r0125, r01, NLDAS, ELM_USRDAT".format(rof_grid))
 
     #--------------------------------------------------------------------
     # Invoke mosart build-namelist - output will go in $CASEBUILD/mosartconf