Directions: From Idaho Springs, follow 103 south towards Mt. Evans.  Follow the road as it winds past picnic areas and trailheads and eventually reaches Echo Lake. There is a large parking area just off the road but if that is full, you can turn right just before the lake and follow a good dirt road to another parking area with restrooms.  
Echo Lake is a popular picnic and camping spot that is located within the Arapaho National Forest but owned and managed by Denver Mountain Parks.  The lake is one the main hubs for visitors to the Mt. Evans Recreation Area and the starting place for various trails leading into the Mt. Evans Wilderness, such as the very popular (and magnificent) Chicago Lakes Trail.  

Echo Lake is a busy park. This is not the place to come to for peace and quiet unless you visit in the wee hours of the morning or at dusk on a weekday, or in the winter.  However, the park is a great place for an easy hike, terrific for kids, or just if you want to spend a little time at high altitude without too much effort.  

The main starting place for the trail is the west end of the lake, but you can also start from the Echo Lake Lodge (restaurant and gift shop) on the eastern shore.  The trail follows the western shore of the lake for a little ways before entering pine forest for the remainder of the hike.  While there are a few trails connecting to the southern shore, the Echo Lake Trail itself is somewhat removed from the lake, through the forest.  
Oddly, enough, the trail does not loop around the entire lake.  If you want to make a loop out of it, you need to walk along 103 for a little ways.