diff --git a/compass/machines/chicoma-cpu.cfg b/compass/machines/chicoma-cpu.cfg
index 70a2256f6d..34211cf53f 100644
--- a/compass/machines/chicoma-cpu.cfg
+++ b/compass/machines/chicoma-cpu.cfg
@@ -28,6 +28,8 @@ spack = /usr/projects/e3sm/compass/chicoma-cpu/spack
 # pnetcdf as E3SM (spack modules are used otherwise)
 use_e3sm_hdf5_netcdf = True
 
+# location of a spack mirror for compass to use
+spack_mirror = /usr/projects/e3sm/compass/chicoma-cpu/spack/spack_mirror
 
 # The parallel section describes options related to running jobs in parallel
 [parallel]