diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b905b087..27b39360 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -27,7 +27,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest]
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
+        python-version: ["3.10", "3.11", "3.12"]
     steps:
       - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python-version }}
@@ -63,7 +63,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v4
         with:
-          python-version: 3.9
+          python-version: "3.10"
           cache: pip
       - run: pip install --upgrade coverage[toml]
       - uses: actions/download-artifact@v4
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 8c83c31b..05b5aefb 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -18,7 +18,7 @@ jobs:
     - name: Set up Python ubuntu-latest
       uses: actions/setup-python@v4
       with:
-        python-version: '3.9'  # Should always be the minimum supported Python version
+        python-version: '3.10'  # Should always be the minimum supported Python version
         cache: 'pip'
         cache-dependency-path': 'requirements.txt'
     - name: Install dependencies
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index de4e221b..dde8d987 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,7 +1,7 @@
 ---
 # See https://pre-commit.com for more information
 default_language_version:
-  python: python3.9
+  python: python3.10
 
 # See https://pre-commit.com/hooks.html for more hooks
 repos:
diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index e0652ef0..e2a2913c 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -9,7 +9,7 @@ version: 2
 build:
     os: ubuntu-22.04
     tools:
-        python: "3.9"
+        python: "3.10"
         # You can also specify other tool versions:
         # nodejs: "19"
         # rust: "1.64"
diff --git a/docs/source/for_beta_testers/beta_testing.rst b/docs/source/for_beta_testers/beta_testing.rst
index 44e24315..6898e9e3 100644
--- a/docs/source/for_beta_testers/beta_testing.rst
+++ b/docs/source/for_beta_testers/beta_testing.rst
@@ -70,7 +70,7 @@ We provide steps for working in one of `GBO data reduction hosts <https://greenb
 
 .. tab:: Outside of GBO
 
-    Create a `Python3.9+` virtual environment
+    Create a `Python3.10+` virtual environment
 
     .. code:: bash
 
diff --git a/docs/source/for_developers/manage_requirements.rst b/docs/source/for_developers/manage_requirements.rst
index ba24a8b5..3c481f82 100644
--- a/docs/source/for_developers/manage_requirements.rst
+++ b/docs/source/for_developers/manage_requirements.rst
@@ -61,14 +61,14 @@ You first need to add the package to `pyproject.toml`. Locate the section of the
 Step 2: Compile `requirements.txt`
 ==================================
 
-Using the lowest supported version of Python (currently 3.9), do the following:
+Using the lowest supported version of Python (currently 3.10), do the following:
 
 .. code-block:: bash
 
     $ cd /path/to/dysh
-    $ source /path/to/dysh-venv-py3.9/bin/activate
-   (dysh-venv-py3.9) $ pip install pip-tools
-   (dysh-venv-py3.9) $ pip-compile -o requirements.txt pyproject.toml
+    $ source /path/to/dysh-venv-py3.10/bin/activate
+   (dysh-venv-py3.10) $ pip install pip-tools
+   (dysh-venv-py3.10) $ pip-compile -o requirements.txt pyproject.toml
 
 Step 3: Validate new requirements
 =================================
@@ -86,7 +86,7 @@ Compiling requirements on Windows
 Sometimes, compiling `requirements.txt` on a Windows machine can result in requirements which fail on the other operating systems. This will result in your GitHub Actions only succeeding on Windows machines, like so:
 
 .. figure:: img/requirements_fail_windows.png
-    :alt: A screenshot of a GitHub Actions summary of 12 tests. The "windows-latest" tests have green check marks, indicating success, for all 4 versions of Python (3.9 to 3.12). The "ubuntu-latest" and "macos-latest" ones all have red x's, indicating failure.
+    :alt: A screenshot of a GitHub Actions summary of 9 tests. The "windows-latest" tests have green check marks, indicating success, for all 3 versions of Python (3.10 to 3.12). The "ubuntu-latest" and "macos-latest" ones all have red x's, indicating failure.
 
 **Solution:** Compile `requirements.txt` on a non-Windows machine, like the Linux ones at GBO.
 
diff --git a/pyproject.toml b/pyproject.toml
index 4b7def3a..6354fe0a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -2,7 +2,7 @@
 name = "dysh"
 description = ''
 readme = "README.md"
-requires-python = ">=3.9"
+requires-python = ">=3.10,<3.13"
 license = {file = "LICENSE"}
 keywords = []
 dynamic = ["version"]
@@ -16,10 +16,6 @@ authors = [
 classifiers = [
   "Development Status :: 3 - Alpha",
   "Programming Language :: Python",
-  "Programming Language :: Python :: 3.9",
-  "Programming Language :: Python :: 3.10",
-  "Programming Language :: Python :: 3.11",
-  "Programming Language :: Python :: 3.12",
   "Programming Language :: Python :: Implementation :: CPython",
 ]
 dependencies = [
@@ -96,7 +92,7 @@ cov = "pytest --cov-report=xml --cov-config=pyproject.toml --cov=src/dysh --cov=
 
 # Run tests across all supported version of Python
 [[tool.hatch.envs.test.matrix]]
-python = ["39", "310", "311", "312"]
+python = ["310", "311", "312"]
 
 [tool.hatch.build.targets.sdist]
 include = ["/src", "/tests", "/bin"]
diff --git a/requirements.txt b/requirements.txt
index 2b62c49e..509d459e 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,5 @@
 #
-# This file is autogenerated by pip-compile with Python 3.9
+# This file is autogenerated by pip-compile with Python 3.11
 # by the following command:
 #
 #    pip-compile --extra=dev --extra=nb --no-emit-trusted-host --output-file=requirements.txt pyproject.toml
@@ -121,11 +121,6 @@ docutils==0.18.1
     #   myst-parser
     #   pydata-sphinx-theme
     #   sphinx
-exceptiongroup==1.2.0
-    # via
-    #   anyio
-    #   ipython
-    #   pytest
 executing==2.0.1
     # via stack-data
 fastjsonschema==2.19.0
@@ -161,17 +156,8 @@ imagesize==1.4.1
 importlib-metadata==6.8.0
     # via
     #   asdf
-    #   build
     #   jupyter-cache
-    #   jupyter-client
-    #   jupyter-lsp
-    #   jupyterlab
-    #   jupyterlab-server
     #   myst-nb
-    #   nbconvert
-    #   sphinx
-importlib-resources==6.1.1
-    # via matplotlib
 iniconfig==2.0.0
     # via pytest
 ipdb==0.13.13
@@ -558,15 +544,6 @@ terminado==0.18.0
     #   jupyter-server-terminals
 tinycss2==1.2.1
     # via nbconvert
-tomli==2.0.1
-    # via
-    #   build
-    #   coverage
-    #   ipdb
-    #   jupyterlab
-    #   numpydoc
-    #   pip-tools
-    #   pytest
 tornado==6.3.3
     # via
     #   ipykernel
@@ -597,8 +574,6 @@ types-python-dateutil==2.8.19.14
     # via arrow
 typing-extensions==4.8.0
     # via
-    #   async-lru
-    #   ipython
     #   myst-nb
     #   pydata-sphinx-theme
     #   sqlalchemy
@@ -625,9 +600,7 @@ wheel==0.43.0
 widgetsnbextension==4.0.9
     # via ipywidgets
 zipp==3.17.0
-    # via
-    #   importlib-metadata
-    #   importlib-resources
+    # via importlib-metadata
 
 # The following packages are considered to be unsafe in a requirements file:
 # pip