In general, you only need a single Router to power your entire site. However, if you have reason to do so, you can easily include multiple Routers, and Backbone will happily allow this. If two or more Routers on the same page match a particular route, Backbone will trigger the route from the first Router with a matching route defined.

There are two main reasons why you should use multiple Routers. The first reason is to separate your routing into logical groups. For instance, in an earlier example, we used a conditional to add certain admin-only routes to the Router class when the current user was an administrator. If our site has enough of these routes, it might make sense to create a separate Router for the admin-only routes, as follows:

var NormalRouter = Backbone.Router({
     routes: {
        // routes for all users would go here
    }
};
var AdminRouter = Backbone.Router({
     routes: {
        // routes for admin users only would go here
    }
};
new NormalRouter...