diff --git a/.github/workflows/continuous-integration.yml b/.github/workflows/continuous-integration.yml
index 911617d..faaa6fa 100644
--- a/.github/workflows/continuous-integration.yml
+++ b/.github/workflows/continuous-integration.yml
@@ -51,8 +51,11 @@ jobs:
         uses: conda-incubator/setup-miniconda@v2
         with:
           auto-update-conda: true
+          environment-file: environment.yml
           python-version: ${{ matrix.python-version }}
-      - name: Update Conda's environemnt
-        run: conda env update -f environment.yml -n test
+      - name: update certs so PROJ can download the us_noaa_cshpgn.tif file
+        run: |
+          sudo mkdir -p /etc/pki/tls/certs
+          sudo curl https://curl.se/ca/cacert.pem -o /etc/pki/tls/certs/ca-bundle.crt
       - name: Execute linters and test suites
         run: ./scripts/cibuild
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 70c249a..e86088a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 
+### Added
+
+- Add Projection Extension field proj:centroid ([#38](https://github.com/stactools-packages/naip/pull/38))
+
 ## [v0.3.1] - 2023-02-24
 
 ### Fixed
diff --git a/setup.cfg b/setup.cfg
index 06b3f1c..b89e2f6 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -31,6 +31,5 @@ packages = find_namespace:
 install_requires =
     stactools >= 0.4.3
     pystac >= 1.5 # for GridExtension class
-
 [options.packages.find]
 where = src
diff --git a/src/stactools/naip/stac.py b/src/stactools/naip/stac.py
index 8f117bb..0e42ce3 100644
--- a/src/stactools/naip/stac.py
+++ b/src/stactools/naip/stac.py
@@ -7,6 +7,7 @@
 import fsspec
 import pystac
 import rasterio as rio
+import shapely
 from lxml import etree
 from pystac.extensions.eo import EOExtension
 from pystac.extensions.grid import GridExtension
@@ -15,7 +16,6 @@
 from pystac.extensions.raster import DataType, RasterBand, RasterExtension
 from pystac.extensions.scientific import CollectionScientificExtension, Publication
 from pystac.utils import str_to_datetime
-from shapely.geometry import box, mapping, shape
 from stactools.core.io import read_text
 from stactools.core.io.xml import XmlElement
 from stactools.core.projection import reproject_geom
@@ -138,7 +138,10 @@ def create_item(
         original_bbox = list(ds.bounds)
         transform = list(ds.transform)
         geom = reproject_geom(
-            ds.crs, "epsg:4326", mapping(box(*ds.bounds)), precision=6
+            ds.crs,
+            "epsg:4326",
+            shapely.geometry.mapping(shapely.geometry.box(*ds.bounds)),
+            precision=6,
         )
 
     if fgdc_metadata_href is not None:
@@ -198,7 +201,9 @@ def create_item(
 
     item_id = naip_item_id(state, resource_desc)
 
-    bounds = list(shape(geom).bounds)
+    shapely_shape = shapely.geometry.shape(geom)
+    bounds = list(shapely_shape.bounds)
+    centroid = shapely_shape.centroid
 
     dt = dt + timedelta(hours=16)  # UTC is +4 ET, so is around 9-12 AM in CONUS
     properties = {"naip:state": state, "naip:year": year}
@@ -222,6 +227,7 @@ def create_item(
     projection.shape = image_shape
     projection.bbox = original_bbox
     projection.transform = transform
+    projection.centroid = {"lat": round(centroid.y, 5), "lon": round(centroid.x, 5)}
 
     # Grid Extension
     grid = GridExtension.ext(item, add_if_missing=True)
diff --git a/tests/test_stac.py b/tests/test_stac.py
index 5bdda10..84023f7 100644
--- a/tests/test_stac.py
+++ b/tests/test_stac.py
@@ -1,6 +1,8 @@
 import unittest
 from datetime import datetime
 
+import pytest
+from pystac.extensions.projection import ProjectionExtension
 from pystac.extensions.raster import DataType, RasterExtension
 from pystac.extensions.scientific import CollectionScientificExtension
 
@@ -38,6 +40,10 @@ def test_create_item_txt(self):
             self.assertEqual(raster_band.data_type, DataType.UINT8)
             self.assertEqual(raster_band.unit, "none")
 
+        projection = ProjectionExtension.ext(item)
+        projection.centroid["lat"] == pytest.approx(30.96876)
+        projection.centroid["lon"] == pytest.approx(-85.90624)
+
     # test stac on year = 2020
     def test_create_item_xml(self):
         item = create_item(
@@ -101,7 +107,6 @@ def test_create_item_xml_ext(self):
             "data-files/m_3211605_ne_11_060_20200415_20200730.xml",
             "data-files/m_3211605_ne_11_060_20200415_20200730_missing_resource_desc.xml",
         ]:
-
             item = create_item(
                 "ca",
                 "2020",