Davis, CA is itself very flat, but what are the hikes with the most elevation gain located within 20 minutes, 30 minutes, and 1 hour drive of Davis? Looking for hikes that could be easily accessed after work on a weekday.

The most elevation you're going to get (without having to go up and down the same trail many times) is Mount Diablo, about 1 hour away from Davis. The shortest round-trip route from bottom to top and back is ~10 miles with ~3.3k feet elevation gain, but there are so many trails and sub-peaks that you can easily add miles and elevation. For example, I routinely do a 17-mile loop with 6.1k elevation gain, tagging 4 "peaks" and a waterfall in the process.

Another option (closer to Davis and with less miles/elevation) would be around Lake Berryessa (a 40-minute drive from Davis?). Specifically, you have the Stebbins Cold Canyon Reserve on the Eastern-side of the lake, although I think it is currently closed. There, you'll be able to do a ~5-mile loop with ~1.5k elevation gain.

Those would be my top choices, but I'm eager to see what others suggest...

Diablo is a bit more than an hour away? My memory is pretty shot as it was awhile ago when I was around the area. Cold canyon was always my favorite, but I do believe it burned down? There is an alright bouldering area around as well.

"Davis is itself very flat" - that is something of an understatement. Anyway, for some exercise after work I would recommend the hills behind Lagoon Valley Park in Vacaville. If you exit WB I-80 at the Pena Adobe exit and cross over the freeway you can park for free along the road. About 30 minutes west of Davis. You can get about 600-700 feet of elevation gain running up and down the fire roads. That's where I train when I'm planning a backpack trip.

Oh, and I forgot to mention, when you get to the top of the ridge behind Lagoon Valley Park you have an awesome view of the worlds largest prison complex.

This is just about an hour from Davis.

http://www.summitpost.org/southwest-ridge-route/254513/c-153520



Fiske/Lowery are just down the roads also.

Berryessa Peak 3k+ gain

One good thing about Davis is that Tahoe is just up the road. I love Tahoe.