diff --git a/lemon/Makefile.am b/lemon/Makefile.am
--- a/lemon/Makefile.am
+++ b/lemon/Makefile.am
@@ -30,6 +30,7 @@
         lemon/dim2.h \
 	lemon/error.h \
         lemon/graph_to_eps.h \
+        lemon/grid_graph.h \
 	lemon/kruskal.h \
 	lemon/lgf_reader.h \
 	lemon/lgf_writer.h \