Reddit mentions of Day Hiking Los Angeles: City Parks / Santa Monica Mountains / San Gabriel Mountains

Not to be a smartass but how much is several?

If you've recently re-located, I have to recommend, at least at some point, catch the redwoods and sequoias almost anywhere in California. They create a great deal of shade which means often lush green ground cover below. Sequoia and King's Canyon parks are about 4 hours North of LA (hence my first question).

If you head into the sierras, there are various sorts of forests, meadows and green rolling hills worth exploring (you can spend a lifetime doing so).

Closer to LA, you have the Angeles National Forest and associated trails and ranges. There are pine forests, some creeks and rivers. These mountains are quite arid, rising above the LA Basin and the high desert towards the North. It may take some getting used to but it's really your back yard. Switzer Falls is a pretty quick drive and recommended. Eaton Canyon is closer, if you're in Pasadena but can be a bit of a crowd scene. I've never gotten around to it but Malibu has legendary trails green and close to the ocean.

Check out Casey Schreiner's book, Day Hiking Los Angeles and website. I can't recommend those highly enough. The kindle version you can load on your phone and bring with you on your hikes. Most of those quick day hikes are going to be great. Don't overlook the epic parks in LA like Griffith, Elysian, the Arroyo in Pasadena, Runyon and other canyons in the hills. I have to recommend also, some from his book and some from others, The San Gabrielino Trail, The San Gabriel River and we have some interesting parks based around flood control basins that are sprawling multi-use recreation areas such as the Sepulveda dam, Whittier Narrows and The Santa Fe Dam (I don't know a ton about those but intend to in the future).

Drive up the Crest (Highway 2 out North of Foothill) and you will be transported to the mountains within minutes. You can drive this route for hours till you come out the other side. Literally everywhere along that road is going to be a nice break from the city. In these areas, you're going to experience an elevation gain that takes some by surprise and it's quite hot so stay hydrated, be prepared, don't overdo it and you'll want to pick up a wilderness pass so you can park.

I use Day Hiking Los Angeles to find trails to take our 2yo on. We like Switzer Falls, Lake Hollywood Trail, and Beaudry Loop. He rides in his carrier for the most part, but gets to play at the destination. The AllTrails app is a great way to track your progress.