diff --git a/.github/workflows/mac.yml b/.github/workflows/mac.yml
new file mode 100644
index 0000000..85debec
--- /dev/null
+++ b/.github/workflows/mac.yml
@@ -0,0 +1,85 @@
+
+name: CI MacOS
+
+on:
+  workflow_dispatch:
+
+jobs:
+
+  mac:
+
+    strategy:
+      matrix:
+        py-version: ['3.10']
+      fail-fast: false
+    name: Python ${{ matrix.py-version }}
+
+    runs-on: macos-latest
+    timeout-minutes: 180
+    env:
+      MPIEXEC_FLAGS: "--allow-run-as-root --oversubscribe"
+      PYNUCLEUS_BUILD_PARALLELISM: 3
+      SUITESPARSE_INCLUDE_DIR: /usr/local/Cellar/brewsci-suite-sparse/4.5.5_2/include
+      SUITESPARSE_LIBRARY_DIR: /usr/local/Cellar/brewsci-suite-sparse/4.5.5_2/lib
+      LDFLAGS: -L/usr/local/opt/brewsci-metis/lib -L/usr/local/opt/brewsci-parmetis/lib
+      CPPFLAGS: -I/usr/local/opt/brewsci-metis/include -I/usr/local/opt/brewsci-parmetis/include
+
+    steps:
+    - name: Check out repo
+      uses: actions/checkout@v3
+
+    - name: Pull ccache cache
+      if: always()
+      id: ccache-restore
+      uses: actions/cache/restore@v3
+      with:
+        path: /home/runner/.cache/ccache
+        key: ccache-mac-${{ matrix.py-version }}
+
+    - name: Setup GNU Fortran
+      uses: modflowpy/install-gfortran-action@v1
+
+    - uses: actions/setup-python@v4
+      with:
+        python-version: ${{ matrix.py-version }}
+
+    - name: Install packages
+      run: |
+        brew install open-mpi ccache
+        brew tap brewsci/num
+        brew install brewsci-metis brewsci-parmetis brewsci-suite-sparse
+
+    - name: Get ccache config dir
+      if: always()
+      run: ccache --show-config
+
+    - name: Install Python dependencies
+      run: make prereq && make prereq-extra
+
+    - name: Install
+      run: make install
+
+    - name: Remove ccache cache
+      if: ${{ steps.ccache-restore.outputs.cache-hit }}
+      shell: bash
+      env:
+        GH_TOKEN: ${{ github.token }}
+      run: |
+        gh extension install actions/gh-actions-cache
+        gh actions-cache delete ccache-mac-${{ matrix.py-version }} --confirm
+      continue-on-error: true
+
+    - name: Push ccache cache
+      if: always()
+      uses: actions/cache/save@v3
+      with:
+        path: /home/runner/.cache/ccache
+        key: ccache-mac-${{ matrix.py-version }}
+
+    - name: Ccache report
+      if: always()
+      run: ccache -s
+
+    - name: Run tests
+      if: always()
+      run: python3 -m pytest --junit-xml=test-results-mac-${{ matrix.py-version }}.xml -k "testFractional[interval-const0.75-knownSolution-P1-cg-mg-H2" tests/