diff --git a/docs/changelog.txt b/docs/changelog.txt
index f828dbf81..4cdfe18a2 100644
--- a/docs/changelog.txt
+++ b/docs/changelog.txt
@@ -56,6 +56,9 @@ changelog.txt uses a syntax similar to RST, with a few special sequences:
 - `quickfort-library-guide`: added light aquifer tap and pump stack blueprints (with step-by-step usage guides) to the quickfort blueprint library
 - `quickfort`: Dreamfort blueprint set improvements: added iron and flux stock level indicators on the industry level
 
+## API
+- ``Buildings::findCivzonesAt()``: lookups now complete in constant time instead of linearly scanning through all civzones in the game
+
 ## Lua
 - ``argparse.processArgsGetopt()``: you can now have long form parameters that are not an alias for a short form parameter. For example, you can now have a parameter like ``--longparam`` without needing to have an equivalent one-letter ``-l`` param.
 - ``dwarfmode.enterSidebarMode()``: ``df.ui_sidebar_mode.DesignateMine`` is now a suported target sidebar mode