a super-bare-bones implementation of a reactive window.location (include this somewhere on the client in a Meteor app)

location.js

var Location = {};

this.Location = Location;

Location.dep = new Deps.Dependency;
Location.state = window.history.state;

window.onpopstate = function(event){
	Location.state = event.state;
	// note that popstate gets fired on initial page load in Webkit,
	// but not in Firefox ... 
	Location.dep.changed();
};

Location.getState = function() {
	var self = this;
	self.dep.depend();
	// Return the state we store, not the built-in, just in case
	// we decide to store extra data with the state later.
	return self.state;
};

Location.go = function( /* arguments */ ) {
	var self = this;
	window.history.go(arguments);
	self.dep.changed();
};

Location.pushState = function( /* arguments */ ) {
	var self = this;
	window.history.pushState(arguments);
	self.dep.changed();
};

Location.replaceState = function( /* arguments */ ) {
	var self = this;
	window.history.replaceState(arguments);
	self.dep.changed();
};

Location.forward = function() {
	var self = this;
	window.history.forward();
	self.dep.changed();
};

Location.back = function() {
	var self = this;
	window.history.back();
	self.dep.changed();
};