diff --git a/campus/campus.go b/campus/campus.go
index 0e35391..ac537a3 100644
--- a/campus/campus.go
+++ b/campus/campus.go
@@ -1,3 +1,4 @@
+// package campus provides methods for working with the SFO airport campus.
 package campus
 
 // type Campus is a lightweight data structure to represent the SFO campus with pointers its descendants.