diff --git a/Dockerfile b/Dockerfile
index aa1a3ab4..65dfbe5f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -37,8 +37,6 @@ EXPOSE 80
 
 COPY . /
 
-ONBUILD COPY mapserver.map /etc/mapserver/
-
 ENTRYPOINT ["/docker-entrypoint.sh"]
 
 CMD ["apache2", "-DFOREGROUND"]
diff --git a/README.md b/README.md
index 5484c60f..15a1ac4f 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,8 @@ COPY *.map /etc/mapserver/
 COPY *.sh *.env /docker-entrypoint.d/
 ```
 
+The main mapfile should be `/etc/mapserver/mapserver.map`.
+
 Or you can use the image as is and mount volumes to customize it.