diff --git a/api/models/route.go b/api/models/route.go
index 9ab6c3eff..c21642990 100644
--- a/api/models/route.go
+++ b/api/models/route.go
@@ -15,15 +15,16 @@ const (
 )
 
 var (
+	ErrInvalidPayload      = errors.New("Invalid payload")
+	ErrRoutesAlreadyExists = errors.New("Route already exists")
 	ErrRoutesCreate        = errors.New("Could not create route")
-	ErrRoutesUpdate        = errors.New("Could not update route")
-	ErrRoutesRemoving      = errors.New("Could not remove route from datastore")
 	ErrRoutesGet           = errors.New("Could not get route from datastore")
 	ErrRoutesList          = errors.New("Could not list routes from datastore")
-	ErrRoutesAlreadyExists = errors.New("Route already exists")
-	ErrRoutesNotFound      = errors.New("Route not found")
 	ErrRoutesMissingNew    = errors.New("Missing new route")
-	ErrInvalidPayload      = errors.New("Invalid payload")
+	ErrRoutesNotFound      = errors.New("Route not found")
+	ErrRoutesPathImmutable = errors.New("Could not update route - path is immutable")
+	ErrRoutesRemoving      = errors.New("Could not remove route from datastore")
+	ErrRoutesUpdate        = errors.New("Could not update route")
 )
 
 type Routes []*Route
diff --git a/api/server/routes_test.go b/api/server/routes_test.go
index a03e4a6a1..672fcd35c 100644
--- a/api/server/routes_test.go
+++ b/api/server/routes_test.go
@@ -203,7 +203,17 @@ func TestRouteUpdate(t *testing.T) {
 					Path:    "/myroute/do",
 				},
 			},
-		}, "/v1/apps/a/routes/myroute/do", `{ "route": { "image": "iron/hello", "path": "/myroute" } }`, http.StatusOK, nil},
+		}, "/v1/apps/a/routes/myroute/do", `{ "route": { "image": "iron/hello" } }`, http.StatusOK, nil},
+
+		// Addresses #381
+		{&datastore.Mock{
+			Routes: []*models.Route{
+				{
+					AppName: "a",
+					Path:    "/myroute/do",
+				},
+			},
+		}, "/v1/apps/a/routes/myroute/do", `{ "route": { "path": "/otherpath" } }`, http.StatusForbidden, nil},
 	} {
 		rnr, cancel := testRunner(t)
 		router := testRouter(test.ds, &mqs.Mock{}, rnr, tasks)
diff --git a/api/server/routes_update.go b/api/server/routes_update.go
index 108404a3b..563b154a3 100644
--- a/api/server/routes_update.go
+++ b/api/server/routes_update.go
@@ -30,6 +30,12 @@ func handleRouteUpdate(c *gin.Context) {
 		return
 	}
 
+	if wroute.Route.Path != "" {
+		log.Debug(models.ErrRoutesPathImmutable)
+		c.JSON(http.StatusForbidden, simpleError(models.ErrRoutesPathImmutable))
+		return
+	}
+
 	wroute.Route.AppName = c.Param("app")
 	wroute.Route.Path = path.Clean(c.Param("route"))
 
diff --git a/docs/routes.md b/docs/routes.md
new file mode 100644
index 000000000..5ba7e619e
--- /dev/null
+++ b/docs/routes.md
@@ -0,0 +1,21 @@
+# Routes
+
+Each application has several functions represented through routes.
+
+## Route level configuration
+
+When creating or updating an app, you can pass in a map of config variables.
+
+`config` is a map of values passed to the route runtime in the form of
+environment variables.
+
+Note: Route level configuration overrides app level configuration.
+
+```sh
+fn routes create --config k1=v1 --config k2=v2 myapp /path image
+```
+
+## Notes
+
+Route paths are immutable. If you need to change them, the appropriate approach
+is to add a new route with the modified path.
\ No newline at end of file
diff --git a/docs/swagger.yml b/docs/swagger.yml
index 4eb488a71..460f161dd 100644
--- a/docs/swagger.yml
+++ b/docs/swagger.yml
@@ -322,6 +322,7 @@ definitions:
           path:
             type: string
             description: URL path that will be matched to this route
+            readOnly: true
           image:
             description: Name of Docker image to use in this route. You should include the image tag, which should be a version number, to be more accurate. Can be overridden on a per route basis with route.image.
             type: string