diff --git a/flake.nix b/flake.nix
index fd91690d5fc78..8d0755a4c2aa2 100644
--- a/flake.nix
+++ b/flake.nix
@@ -148,6 +148,7 @@
           '';
 
           GDAL_DATA = "${pkgs.gdal}/share/gdal";
+          PROJ_DATA = "${pkgs.proj}";
 
           __darwinAllowLocalNetworking = true;
         };