Lake Miramar, or Miramar Resevoir, is city-owned reservoir near Scripps Ranch, San Diego. The lake is a great spot for hiking, biking, boating, and fishing. The hiking trail is both child and dog friendly. There is a large picnic area perfect for stopping to have lunch.
There are two trails that run around the perimeter of the reservoir: one paved and one unpaved. They are both just under 5 miles, and mostly flat with some sharp turns. The paved path is popular for bikes and families with strollers.
The unpaved trail is closer to the lake, and offers a more scenic view (although the entire park is beautiful). There are some large rocks along the path that are a good place to sit and look out at the peaceful water.
Because the trail is somewhat long, it's a good idea to keep track of how long you have been walking. You may want to turn around instead of walking around the entire lake. This is especially important if you are hiking close to sunset.