diff --git a/pkgs/development/libraries/proj/default.nix b/pkgs/development/libraries/proj/default.nix
index 376cb36edd61..a8e42fb6fb17 100644
--- a/pkgs/development/libraries/proj/default.nix
+++ b/pkgs/development/libraries/proj/default.nix
@@ -7,36 +7,43 @@
 , libtiff
 , curl
 , gtest
+, nlohmann_json
 }:
 
 stdenv.mkDerivation rec {
   pname = "proj";
-  version = "8.2.1";
+  version = "9.0.0";
 
   src = fetchFromGitHub {
     owner = "OSGeo";
     repo = "PROJ";
     rev = version;
-    hash = "sha256-tnaIqYKgYHY1Tg33jsKYn9QL8YUobgXKbQsodoCXNys=";
+    sha256 = "sha256-zMP+WzC65BFz8g8mF5t7toqxmxCJePysd6WJuqpe8yg=";
   };
 
-  outputs = [ "out" "dev"];
+  outputs = [ "out" "dev" ];
 
   nativeBuildInputs = [ cmake pkg-config ];
 
-  buildInputs = [ sqlite libtiff curl ];
+  buildInputs = [ sqlite libtiff curl nlohmann_json ];
 
   checkInputs = [ gtest ];
 
   cmakeFlags = [
     "-DUSE_EXTERNAL_GTEST=ON"
     "-DRUN_NETWORK_DEPENDENT_TESTS=OFF"
+    "-DNLOHMANN_JSON_ORIGIN=external"
   ];
 
-  preCheck = ''
-    export HOME=$TMPDIR
-    export TMP=$TMPDIR
-  '';
+  preCheck =
+    let
+      libPathEnvVar = if stdenv.isDarwin then "DYLD_LIBRARY_PATH" else "LD_LIBRARY_PATH";
+    in
+      ''
+        export HOME=$TMPDIR
+        export TMP=$TMPDIR
+        export ${libPathEnvVar}=$PWD/lib
+      '';
 
   doCheck = true;