u/Fearless_Day2607

San Bruno Mountain lies just south of the San Francisco city limits in a state/county park and is the most prominent peak in San Mateo County. The county high point is not accessible to the public as it's in someone's front yard in the Santa Cruz mountains (see Peakbagger for info about legal access), but San Bruno Mountain is a good substitute, and has much better views anyway.

My brother lives a few miles away from here so while I was visiting him this past winter, I took the opportunity to bag this peak, by bike. It's a very bikeable peak as there is a paved access road (closed to motor vehicles) pretty much all the way to the summit - then it's just a short scramble to get to the actual highest point. There's also a fire road that goes along the ridge but bikes aren't allowed there.

The views of San Francisco and the bay are excellent. You can also see Mount Diablo and Mount Tamalpais (both of which are CoHPs) in the distance.

Besides the scenery, San Bruno Mountain is critical habitat for several endangered species of butterfly as well as flora. The San Bruno elfin, Mission Blue butterfly, and Callippe silverspot butterfly are all endemic to the Bay Area and their largest populations can be found on this mountain. San Bruno Mountain underwent a great deal of development pressure in the past, including a proposal that sought to level the top of the mountain and use it to fill in the bay. It is only due to the tireless efforts of local activists that San Bruno Mountain is largely protected today.

I visited this park while bikepacking the Grand Illinois Trail last month. Camped there and hiked several of the trails. This was my first time seeing the Mississippi River (other than from a plane) and it was definitely a highlight of the trip, with some of the best scenery Illinois has to offer. Of the two trail systems (north and south), I would recommend the south trail system as it has better views.

The campground was good - $10 non-electric sites with showers, and it was mostly empty (on a weekday) so I had no trouble securing a walk-in site.

Mosquitoes were terrible so if you visit this park, make sure you have enough bug spray. Also, as I was leaving the park I saw a sign informing visitors that there had been bear sightings in the area.