diff --git a/docs/requests.md b/docs/requests.md
index 9140bb964..368755f13 100644
--- a/docs/requests.md
+++ b/docs/requests.md
@@ -113,12 +113,12 @@ state with `disconnected = await request.is_disconnected()`.
 
 Request files are normally sent as multipart form data (`multipart/form-data`).
 
-Signature: `request.form(max_files=1000, max_fields=1000)`
+Signature: `request.form(max_files=1000, max_fields=1000, max_part_size=1024*1024)`
 
-You can configure the number of maximum fields or files with the parameters `max_files` and `max_fields`:
+You can configure the number of maximum fields or files with the parameters `max_files` and `max_fields`; and part size using `max_part_size`:
 
 ```python
-async with request.form(max_files=1000, max_fields=1000):
+async with request.form(max_files=1000, max_fields=1000, max_part_size=1024*1024):
     ...
 ```
 
diff --git a/starlette/_utils.py b/starlette/_utils.py
index 74c9f24f7..a22a27459 100644
--- a/starlette/_utils.py
+++ b/starlette/_utils.py
@@ -75,9 +75,9 @@ def collapse_excgroups() -> typing.Generator[None, None, None]:
     try:
         yield
     except BaseException as exc:
-        if has_exceptiongroups:
+        if has_exceptiongroups:  # pragma: no cover
             while isinstance(exc, BaseExceptionGroup) and len(exc.exceptions) == 1:
-                exc = exc.exceptions[0]  # pragma: no cover
+                exc = exc.exceptions[0]
 
         raise exc
 
diff --git a/starlette/formparsers.py b/starlette/formparsers.py
index 82e2ad195..87d262c1d 100644
--- a/starlette/formparsers.py
+++ b/starlette/formparsers.py
@@ -123,7 +123,6 @@ async def parse(self) -> FormData:
 
 class MultiPartParser:
     max_file_size = 1024 * 1024  # 1MB
-    max_part_size = 1024 * 1024  # 1MB
 
     def __init__(
         self,
@@ -132,6 +131,7 @@ def __init__(
         *,
         max_files: int | float = 1000,
         max_fields: int | float = 1000,
+        max_part_size: int = 1024 * 1024,  # 1MB
     ) -> None:
         assert multipart is not None, "The `python-multipart` library must be installed to use form parsing."
         self.headers = headers
@@ -148,6 +148,7 @@ def __init__(
         self._file_parts_to_write: list[tuple[MultipartPart, bytes]] = []
         self._file_parts_to_finish: list[MultipartPart] = []
         self._files_to_close_on_error: list[SpooledTemporaryFile[bytes]] = []
+        self.max_part_size = max_part_size
 
     def on_part_begin(self) -> None:
         self._current_part = MultipartPart()
diff --git a/starlette/middleware/gzip.py b/starlette/middleware/gzip.py
index 127b91e7a..b677063da 100644
--- a/starlette/middleware/gzip.py
+++ b/starlette/middleware/gzip.py
@@ -13,7 +13,7 @@ def __init__(self, app: ASGIApp, minimum_size: int = 500, compresslevel: int = 9
         self.compresslevel = compresslevel
 
     async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
-        if scope["type"] == "http":
+        if scope["type"] == "http":  # pragma: no branch
             headers = Headers(scope=scope)
             if "gzip" in headers.get("Accept-Encoding", ""):
                 responder = GZipResponder(self.app, self.minimum_size, compresslevel=self.compresslevel)
@@ -88,7 +88,7 @@ async def send_with_gzip(self, message: Message) -> None:
                 await self.send(self.initial_message)
                 await self.send(message)
 
-        elif message_type == "http.response.body":
+        elif message_type == "http.response.body":  # pragma: no branch
             # Remaining body in streaming GZip response.
             body = message.get("body", b"")
             more_body = message.get("more_body", False)
diff --git a/starlette/requests.py b/starlette/requests.py
index a29164d0d..992988a45 100644
--- a/starlette/requests.py
+++ b/starlette/requests.py
@@ -230,7 +230,7 @@ async def stream(self) -> typing.AsyncGenerator[bytes, None]:
                     self._stream_consumed = True
                 if body:
                     yield body
-            elif message["type"] == "http.disconnect":
+            elif message["type"] == "http.disconnect":  # pragma: no branch
                 self._is_disconnected = True
                 raise ClientDisconnect()
         yield b""
@@ -249,8 +249,14 @@ async def json(self) -> typing.Any:
             self._json = json.loads(body)
         return self._json
 
-    async def _get_form(self, *, max_files: int | float = 1000, max_fields: int | float = 1000) -> FormData:
-        if self._form is None:
+    async def _get_form(
+        self,
+        *,
+        max_files: int | float = 1000,
+        max_fields: int | float = 1000,
+        max_part_size: int = 1024 * 1024,
+    ) -> FormData:
+        if self._form is None:  # pragma: no branch
             assert (
                 parse_options_header is not None
             ), "The `python-multipart` library must be installed to use form parsing."
@@ -264,6 +270,7 @@ async def _get_form(self, *, max_files: int | float = 1000, max_fields: int | fl
                         self.stream(),
                         max_files=max_files,
                         max_fields=max_fields,
+                        max_part_size=max_part_size,
                     )
                     self._form = await multipart_parser.parse()
                 except MultiPartException as exc:
@@ -278,9 +285,15 @@ async def _get_form(self, *, max_files: int | float = 1000, max_fields: int | fl
         return self._form
 
     def form(
-        self, *, max_files: int | float = 1000, max_fields: int | float = 1000
+        self,
+        *,
+        max_files: int | float = 1000,
+        max_fields: int | float = 1000,
+        max_part_size: int = 1024 * 1024,
     ) -> AwaitableOrContextManager[FormData]:
-        return AwaitableOrContextManagerWrapper(self._get_form(max_files=max_files, max_fields=max_fields))
+        return AwaitableOrContextManagerWrapper(
+            self._get_form(max_files=max_files, max_fields=max_fields, max_part_size=max_part_size)
+        )
 
     async def close(self) -> None:
         if self._form is not None:  # pragma: no branch
diff --git a/starlette/routing.py b/starlette/routing.py
index 3b3c52968..74daeadb0 100644
--- a/starlette/routing.py
+++ b/starlette/routing.py
@@ -196,7 +196,7 @@ async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
             if scope["type"] == "http":
                 response = PlainTextResponse("Not Found", status_code=404)
                 await response(scope, receive, send)
-            elif scope["type"] == "websocket":
+            elif scope["type"] == "websocket":  # pragma: no branch
                 websocket_close = WebSocketClose()
                 await websocket_close(scope, receive, send)
             return
@@ -398,7 +398,7 @@ def routes(self) -> list[BaseRoute]:
 
     def matches(self, scope: Scope) -> tuple[Match, Scope]:
         path_params: dict[str, typing.Any]
-        if scope["type"] in ("http", "websocket"):
+        if scope["type"] in ("http", "websocket"):  # pragma: no branch
             root_path = scope.get("root_path", "")
             route_path = get_route_path(scope)
             match = self.path_regex.match(route_path)
@@ -481,7 +481,7 @@ def routes(self) -> list[BaseRoute]:
         return getattr(self.app, "routes", [])
 
     def matches(self, scope: Scope) -> tuple[Match, Scope]:
-        if scope["type"] in ("http", "websocket"):
+        if scope["type"] in ("http", "websocket"):  # pragma:no branch
             headers = Headers(scope=scope)
             host = headers.get("host", "").split(":")[0]
             match = self.host_regex.match(host)
diff --git a/tests/test_formparsers.py b/tests/test_formparsers.py
index 64efdbdbc..f781a9ecb 100644
--- a/tests/test_formparsers.py
+++ b/tests/test_formparsers.py
@@ -104,10 +104,10 @@ async def app_read_body(scope: Scope, receive: Receive, send: Send) -> None:
     await response(scope, receive, send)
 
 
-def make_app_max_parts(max_files: int = 1000, max_fields: int = 1000) -> ASGIApp:
+def make_app_max_parts(max_files: int = 1000, max_fields: int = 1000, max_part_size: int = 1024 * 1024) -> ASGIApp:
     async def app(scope: Scope, receive: Receive, send: Send) -> None:
         request = Request(scope, receive)
-        data = await request.form(max_files=max_files, max_fields=max_fields)
+        data = await request.form(max_files=max_files, max_fields=max_fields, max_part_size=max_part_size)
         output: dict[str, typing.Any] = {}
         for key, value in data.items():
             if isinstance(value, UploadFile):
@@ -699,3 +699,43 @@ def test_max_part_size_exceeds_limit(
         response = client.post("/", data=multipart_data, headers=headers)  # type: ignore
         assert response.status_code == 400
         assert response.text == "Part exceeded maximum size of 1024KB."
+
+
+@pytest.mark.parametrize(
+    "app,expectation",
+    [
+        (make_app_max_parts(max_part_size=1024 * 10), pytest.raises(MultiPartException)),
+        (
+            Starlette(routes=[Mount("/", app=make_app_max_parts(max_part_size=1024 * 10))]),
+            does_not_raise(),
+        ),
+    ],
+)
+def test_max_part_size_exceeds_custom_limit(
+    app: ASGIApp,
+    expectation: typing.ContextManager[Exception],
+    test_client_factory: TestClientFactory,
+) -> None:
+    client = test_client_factory(app)
+    boundary = "------------------------4K1ON9fZkj9uCUmqLHRbbR"
+
+    multipart_data = (
+        f"--{boundary}\r\n"
+        f'Content-Disposition: form-data; name="small"\r\n\r\n'
+        "small content\r\n"
+        f"--{boundary}\r\n"
+        f'Content-Disposition: form-data; name="large"\r\n\r\n'
+        + ("x" * 1024 * 10 + "x")  # 1MB + 1 byte of data
+        + "\r\n"
+        f"--{boundary}--\r\n"
+    ).encode("utf-8")
+
+    headers = {
+        "Content-Type": f"multipart/form-data; boundary={boundary}",
+        "Transfer-Encoding": "chunked",
+    }
+
+    with expectation:
+        response = client.post("/", content=multipart_data, headers=headers)
+        assert response.status_code == 400
+        assert response.text == "Part exceeded maximum size of 10KB."
diff --git a/tests/test_routing.py b/tests/test_routing.py
index 6d7e5d154..933fe7c31 100644
--- a/tests/test_routing.py
+++ b/tests/test_routing.py
@@ -565,6 +565,16 @@ def test_url_for_with_double_mount() -> None:
     assert url == "/mount/static/123"
 
 
+def test_url_for_with_root_path_ending_with_slash(test_client_factory: TestClientFactory) -> None:
+    def homepage(request: Request) -> JSONResponse:
+        return JSONResponse({"index": str(request.url_for("homepage"))})
+
+    app = Starlette(routes=[Route("/", homepage, name="homepage")])
+    client = test_client_factory(app, base_url="https://www.example.org/", root_path="/sub_path/")
+    response = client.get("/sub_path/")
+    assert response.json() == {"index": "https://www.example.org/sub_path/"}
+
+
 def test_standalone_route_matches(
     test_client_factory: TestClientFactory,
 ) -> None: