From 6f6c0a33d63198799a685f1de7fecd226ca9d1a5 Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Tue, 3 Oct 2023 18:54:15 +0200
Subject: [PATCH] Backport PR #55363: BUG: ndim of string block incorrect with
 string inference

---
 pandas/core/internals/construction.py   | 2 +-
 pandas/tests/frame/test_constructors.py | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/pandas/core/internals/construction.py b/pandas/core/internals/construction.py
index 05aa9f38bb2b0..8bb6c6b5de7ea 100644
--- a/pandas/core/internals/construction.py
+++ b/pandas/core/internals/construction.py
@@ -383,7 +383,7 @@ def ndarray_to_mgr(
             new_block(
                 dtype.construct_array_type()._from_sequence(data, dtype=dtype),
                 BlockPlacement(slice(i, i + 1)),
-                ndim=1,
+                ndim=2,
             )
             for i, data in enumerate(obj_columns)
         ]
diff --git a/pandas/tests/frame/test_constructors.py b/pandas/tests/frame/test_constructors.py
index a8ab3ce1ba014..e1aa682d763a9 100644
--- a/pandas/tests/frame/test_constructors.py
+++ b/pandas/tests/frame/test_constructors.py
@@ -2743,6 +2743,13 @@ def test_frame_string_inference_array_string_dtype(self):
             df = DataFrame(np.array([["a", "c"], ["b", "d"]]), columns=["a", "b"])
         tm.assert_frame_equal(df, expected)
 
+    def test_frame_string_inference_block_dim(self):
+        # GH#55363
+        pytest.importorskip("pyarrow")
+        with pd.option_context("future.infer_string", True):
+            df = DataFrame(np.array([["hello", "goodbye"], ["hello", "Hello"]]))
+        assert df._mgr.blocks[0].ndim == 2
+
 
 class TestDataFrameConstructorIndexInference:
     def test_frame_from_dict_of_series_overlapping_monthly_period_indexes(self):