diff --git a/.github/workflows/build-timezonefinder.yml b/.github/workflows/build-timezonefinder.yml
new file mode 100644
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+++ b/.github/workflows/build-timezonefinder.yml
@@ -0,0 +1,97 @@
+# SPDX-FileCopyrightText: 2026 The RISE Project
+# SPDX-License-Identifier: MIT
+---
+# This workflow is based on the `make-wheels` job of
+# https://github.com/jannikmi/timezonefinder/blob/8.3.0/.github/workflows/build.yml
+name: Build timezonefinder wheels (riscv64)
+
+on:
+  workflow_dispatch:
+    inputs:
+      version:
+        description: 'timezonefinder version to build (git tag, e.g. 8.3.0)'
+        required: true
+        default: '8.3.0'
+  pull_request:
+    paths:
+      - '.github/workflows/build-timezonefinder.yml'
+
+concurrency:
+  group: ${{ github.workflow }}-${{ inputs.version || '8.3.0' }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read  # to fetch code (actions/checkout)
+
+env:
+  # `inputs.version` is empty on pull_request events; default to 8.3.0 there.
+  TIMEZONEFINDER_VERSION: ${{ inputs.version || '8.3.0' }}
+  MANYLINUX_RISCV64_IMAGE: quay.io/pypa/manylinux_2_39_riscv64
+
+jobs:
+  setup:
+    uses: $/.github/workflows/_setup.yml
+
+  build_wheels:
+    needs: [setup]
+    name: Build timezonefinder ${{ inputs.version || '8.3.0' }} cp311-abi3-manylinux_riscv64
+    runs-on: ubuntu-24.04-riscv
+    timeout-minutes: 90
+    steps:
+      - name: Checkout timezonefinder ${{ env.TIMEZONEFINDER_VERSION }}
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
+        with:
+          repository: jannikmi/timezonefinder
+          ref: ${{ env.TIMEZONEFINDER_VERSION }}
+          persist-credentials: false
+
+      - name: Build wheels
+        uses: pypa/cibuildwheel@1828c10ab37f080699c7b81cea34097c684a7074  # v4.2.0
+        with:
+          output-dir: wheelhouse/
+        env:
+          # Upstream sets py_limited_api in setup.py from cibuildwheel's own
+          # BUILD_ABI3 override (`[[tool.cibuildwheel.overrides]] select = "*"`),
+          # so building on the oldest interpreter it claims (cp311) and letting
+          # cibuildwheel reuse+retest that one wheel on cp312-cp314 matches
+          # upstream's own single `cp311-*` build (gotcha 96).
+          CIBW_BUILD: >-
+            cp311-manylinux_riscv64 cp312-manylinux_riscv64
+            cp313-manylinux_riscv64 cp314-manylinux_riscv64
+          CIBW_MANYLINUX_RISCV64_IMAGE: ${{ env.MANYLINUX_RISCV64_IMAGE }}
+          CIBW_BUILD_FRONTEND: pip
+          # Replaces (not merges into) upstream's [tool.cibuildwheel] environment
+          # overrides, so BUILD_ABI3 (needed for the abi3 tag) is repeated here
+          # alongside our registry (gotcha 107). h3 and numpy have no riscv64
+          # wheel for cp311 on our registry yet, so cp311 skips the test below;
+          # PIP_ONLY_BINARY keeps pip on our registry's cffi/numpy/h3 builds
+          # rather than a newer sourceless PyPI release (gotcha 30).
+          CIBW_ENVIRONMENT: >-
+            BUILD_ABI3=true
+            PIP_EXTRA_INDEX_URL=https://pypi.riseproject.dev/simple/
+            PIP_ONLY_BINARY=cffi,numpy,h3
+          # Upstream's own repair-wheel-command also runs abi3audit via uvx,
+          # which the riscv64 image doesn't carry; cibuildwheel's own default
+          # audit-command already abi3audits every abi3-tagged wheel natively
+          # after this repair step runs, so drop the uvx layer here.
+          CIBW_REPAIR_WHEEL_COMMAND_LINUX: auditwheel repair -w {dest_dir} {wheel}
+          CIBW_TEST_SKIP: cp311-*
+          CIBW_TEST_COMMAND: >-
+            python -c "from timezonefinder import TimezoneFinder; tf = TimezoneFinder(); result = tf.timezone_at(lat=40.5, lng=11.7); assert result == 'Etc/GMT-1', result"
+            && python -c "from timezonefinder.utils import clang_extension_loaded; assert clang_extension_loaded"
+
+      - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a  # v7.0.1
+        with:
+          name: timezonefinder-${{ env.TIMEZONEFINDER_VERSION }}-cp311-abi3-manylinux_riscv64
+          path: wheelhouse/*.whl
+          if-no-files-found: error
+
+  publish:
+    name: Publish timezonefinder ${{ inputs.version || '8.3.0' }}
+    needs: [setup, build_wheels]
+    permissions:
+      contents: write
+      pull-requests: write
+    uses: $/.github/workflows/_publish-wheel.yml
+    with:
+      artifact-pattern: timezonefinder-${{ inputs.version || '8.3.0' }}-*-manylinux_riscv64