diff --git a/pyproject.toml b/pyproject.toml
index 564120b..c4ada00 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -18,6 +18,7 @@ classifiers = ["License :: OSI Approved :: BSD License"]
 [project.optional-dependencies]
 dev = [    
     "geopandas", 
+    "fiona",
     "geojson", 
     "simplification", 
     "pyshp",