diff --git a/src/dexorder/blockstate/state.py b/src/dexorder/blockstate/state.py
index 9f1b2fa..414f3a5 100644
--- a/src/dexorder/blockstate/state.py
+++ b/src/dexorder/blockstate/state.py
@@ -158,7 +158,7 @@ class BlockState:
     def remove_branch(self, branch: Branch, *, remove_series_diffs=True):
         if branch.height == self.height and len(self.branches_by_height[branch.height]) == 1:
             # this is the only branch at this height: compute the new lower height
-            self.height = max(b.height for b in self.branches_by_id.values()) if self.branches_by_id else 0
+            self.height = max(0, *[b.height for b in self.branches_by_id.values() if b is not branch])
         del self.branches_by_id[branch.id]
         by_height = self.branches_by_height.get(branch.height)
         if by_height is not None: