diff --git a/executing/executing.py b/executing/executing.py
index c28091d..6c68683 100644
--- a/executing/executing.py
+++ b/executing/executing.py
@@ -85,6 +85,50 @@ def wrapper(*args):
     # noinspection PyUnresolvedReferences
     text_type = unicode
 
+
+class CachedIntervalList(object):
+    """
+    Poor's man interval datastructure.
+
+    We don't need a full-interval tree but this is much faster to construct
+    and query that a mapping line:nodes, especially when some (nested) nodes
+    span a really large number of lines.
+    """
+
+    _tree = {}  # type: Dict[int, Dict[int, List[Any]]]
+
+    _cache = {} # type: Dict[int, List[Any]]
+
+
+    def add(self, low, high, value):
+        # type: (int, int, Any) -> None
+        assert low <= high
+        self._tree.setdefault(low, {}).setdefault(high, []).append(value)
+        self._cache = {}
+
+    def __getitem__(self, index):
+        # type: (int) -> Any
+        if index not in self._cache:
+            self._cache[index] = self._querry(index)
+        return self._cache[index]
+
+    def _querry(self, index):
+        # type: (int) ->  List[Any]
+
+        acc = []
+        for mn, v in self._tree.items():
+            if mn > index:
+                continue
+            for it in [item for mx, item in v.items() if mx >= index]:
+                acc.extend(it)
+        return acc
+
+    def __init__(self):
+        # type: () -> None
+        self._tree = {}
+        self._cache = {}
+
+
 # Type class used to expand out the definition of AST to include fields added by this library
 # It's not actually used for anything other than type checking though!
 class EnhancedAST(ast.AST):
@@ -233,7 +277,7 @@ def __init__(self, filename, lines):
             lines = [line.decode(encoding) for line in lines]
 
         self.text = text
-        self.lines = [line.rstrip('\r\n') for line in lines]
+        self.lines = text.splitlines()
 
         if sys.version_info[0] == 3:
             ast_text = text
@@ -247,7 +291,7 @@ def __init__(self, filename, lines):
                 for i, line in enumerate(lines)
             ])
 
-        self._nodes_by_line = defaultdict(list)
+        self._nodes_by_line = CachedIntervalList()
         self.tree = None
         self._qualnames = {}
         self._asttokens = None  # type: Optional[ASTTokens]
@@ -261,8 +305,10 @@ def __init__(self, filename, lines):
             for node in ast.walk(self.tree):
                 for child in ast.iter_child_nodes(node):
                     cast(EnhancedAST, child).parent = cast(EnhancedAST, node)
-                for lineno in node_linenos(node):
-                    self._nodes_by_line[lineno].append(node)
+                linenos = node_minmax(node)
+                if linenos:
+                    min_, max_ = linenos[0], linenos[-1]
+                    self._nodes_by_line.add(min_, max_, node)
 
             visitor = QualnameVisitor()
             visitor.visit(self.tree)
@@ -1207,6 +1253,7 @@ def is_ipython_cell_code(code_obj):
     )
 
 
+
 def find_node_ipython(frame, lasti, stmts, source):
     # type: (types.FrameType, int, Set[EnhancedAST], Source) -> Tuple[Optional[Any], Optional[Any]]
     node = decorator = None
@@ -1239,7 +1286,6 @@ def attr_names_match(attr, argval):
         return False
     return bool(re.match(r"^_\w+%s$" % attr, argval))
 
-
 def node_linenos(node):
     # type: (ast.AST) -> Iterator[int]
     if hasattr(node, "lineno"):
@@ -1252,6 +1298,17 @@ def node_linenos(node):
         for lineno in linenos:
             yield lineno
 
+def node_minmax(node):
+    # type: (ast.AST) -> Optional[Tuple[int, int]]
+    if hasattr(node, "lineno"):
+        linenos = [] # type: Sequence[int]
+        if hasattr(node, "end_lineno") and isinstance(node, ast.expr):
+            assert node.end_lineno is not None # type: ignore[attr-defined]
+            return (node.lineno, node.end_lineno) # type: ignore[attr-defined]
+        else:
+            return (node.lineno, node.lineno) # type: ignore[attr-defined]
+    return None
+
 
 if sys.version_info >= (3, 11):
     from ._position_node_finder import PositionNodeFinder as NodeFinder