diff --git a/pkgs/development/libraries/proj/default.nix b/pkgs/development/libraries/proj/default.nix
index c7a316778212..1ff2034a7ba6 100644
--- a/pkgs/development/libraries/proj/default.nix
+++ b/pkgs/development/libraries/proj/default.nix
@@ -9,32 +9,20 @@
 , curl
 , gtest
 , nlohmann_json
+, python3
 }:
 
 stdenv.mkDerivation rec {
   pname = "proj";
-  version = "9.0.0";
+  version = "9.1.0";
 
   src = fetchFromGitHub {
     owner = "OSGeo";
     repo = "PROJ";
     rev = version;
-    sha256 = "sha256-zMP+WzC65BFz8g8mF5t7toqxmxCJePysd6WJuqpe8yg=";
+    hash = "sha256-Upsp72RorV+5PFPHOK3zCJgVTRZ6fSVVFRope8Bp8/M=";
   };
 
-  # https://github.com/OSGeo/PROJ/issues/3206
-  postPatch = ''
-    # NB will not apply once https://github.com/OSGeo/PROJ/pull/3150 is released
-    substituteInPlace cmake/ProjUtilities.cmake \
-      --replace '$\{exec_prefix\}/$'{PROJ_LIB_SUBDIR} '$'{CMAKE_INSTALL_FULL_LIBDIR} \
-      --replace '$\{prefix\}/$'{PROJ_INCLUDE_SUBDIR} '$'{CMAKE_INSTALL_FULL_INCLUDEDIR} \
-      --replace '$\{prefix\}/$'{CMAKE_INSTALL_DATAROOTDIR} '$'{CMAKE_INSTALL_FULL_DATAROOTDIR}
-    substituteInPlace cmake/project-config.cmake.in \
-      --replace '$'{_ROOT}/@INCLUDEDIR@ @CMAKE_INSTALL_FULL_INCLUDEDIR@ \
-      --replace '$'{_ROOT}/@LIBDIR@ @CMAKE_INSTALL_FULL_LIBDIR@ \
-      --replace '$'{_ROOT}/@BINDIR@ @CMAKE_INSTALL_FULL_BINDIR@
-  '';
-
   outputs = [ "out" "dev" ];
 
   nativeBuildInputs = [ cmake pkg-config ];
@@ -62,6 +50,10 @@ stdenv.mkDerivation rec {
 
   doCheck = true;
 
+  passthru.tests = {
+    python = python3.pkgs.pyproj;
+  };
+
   meta = with lib; {
     description = "Cartographic Projections Library";
     homepage = "https://proj.org/";