Black Diamond Mines Regional Preserve — Attraction in Antioch

tl;dr: for those looking to hike the extensive trails here, be prepared to step in cow poop, deal with destroyed trails from the herds, and circumnavigate cows displaying aggressive behavior. Priority at this park appears to be cows people.

Full review: For years I have recommended Black Diamond Mines as my favorite of the EBRPD parks. Unfortunately leadership at this park has apparently decided to prioritize cows over people of late, and appears to be more "publicly subsidized ranch land" than public resource. (Before accusing me of hyperbole, a note that one of the few other hikers I encountered had been driven to carrying a fake cattle prod with him because of the number of times he's encountered aggressive cattle.)

For context, I usually do an 8.5-10 mile loop, so this does not refer to the mine tours or more developed areas. When I visited in late January after a week + without rain, I found that cows lined the trails for nearly the entirety of my 8+ mile hike, and that three times I needed to adjust my trail choice to accommodate either "ornery bulls" as they were described by a fellow hiker, or cows that were anxious of me being near their calves and didn't back down as I called to them/approached. Although the park is supposedly "dogs off-leash", I needed to keep mine on for the entirety of the hike because of the restrictrictions on dogs around livestock.

Not only was the presence of the cows themselves disruptive, but they had torn up the trails to the point that they were nearly impassible, and if I weren't already 4+ miles into my hike, I would have turned around to avoid them. Between trying not to roll my ankle in their hoof prints, and the futility of avoiding stepping in cow poop, it was a long way from being a restful communion with nature and appreciation of the park. (Attached pictures from different sections of trail, as well as a warning on what your shoes may look like after your visit.)

If the park system is so keen on prioritizing grazing in the parks, it would be great to either mark destroyed trails as "closed", or do what Walnut Creek Open Space has previously done and put electric fencing along the trails to keep the cows from destroying them while allowing people to still access the land. I'm not against the multi-use nature of the parks, but please don't call something a public park when in reality it's publicly...

The Black Diamond Mines Regional Preserve is a great open space. Situated between Clayton and Antioch it is out of the way but still close by to many cities in the East Bay. I came here a couple times for long hikes in the morning, the weather was 70 degrees and windy. It can get cold, unless its summer around noon.

It's a relatively large space, smaller that Diablo State Park, but bigger than the Walnut Creek Shell Ridge Open Space. There is a stark, natural beauty to the place that I really like. The only thing you can really hear is the wind. Animal wildlife ranges from small birds to prairie dogs to eagles and of course cattle/turkeys. There are different types of trails including: paved, gravel, hard dirt, and grassy trails. The grassy trails can be hard to see because they are in protected areas so tread carefully. The trails are very extensive, you can walk from Antioch to Clayton if you feel inclined. The trails are not too difficult, but some of the can be a little dangerous if you are not watching where you are going. One thing that does not make sense to me is the lack of any sort of rocks or down trees for people to sit on, this is a big space and the trails are long, so you should rest frequently.

Amenities include 2 parking lots, 1 mile apart from each other, with a trail and road in between them. There is a camp ground 2-3 miles away from the first parking lot, though I did not use it. There are a couple bathrooms and a water fountain at the second parking lot. Some of the trails are in disrepair due to cattle grazing. Some of the trails are hard to walk because of hoof prints that damaged the trail, I had trouble even when wearing boots and there are cow droppings to avoid as well.

Overall I would recommend it for a nice walk or even a long hike.

tldr; Pros: Beautiful location, quiet remoteness, long trails Cons: Cattle grazing damages the trail, lack of...

This place is really amazing, I like to come here. I remember it like it was yesterday, I was in 3rd grade on a field trip here. The hiking trail was really a sight. We crossed grassy hills, areas with dense foliage, not to mention all the important, historically significant mines and the cemetery. They have a strange, interesting, surreal feeling to them, not in in a bad way of course, but there's just a certain mystery to them that I can't put my finger on. The cemetery has lots of interesting historic facts, and some pretty creepy legends. Even now, when I come with my family, I still discover new, beautiful areas. Let me tell you about my favorite one. I came here with the family once, and I said we should go check out this one side of the park. We saw what could possibly be a mountain lion den (yes there are mountain lions here but I haven't encountered one in all my trips here, but still be cautious), we struggled up slippery mossy rocks, but eventually, we stumbled across a beautiful, eye catching little clearing amongst the woods. It looks like it could be a background of those new-fangled telephones the kiddos have nowadays. There are branches that give shade but also leave room for light to make this place more beautiful, and there is also moss everywhere, with boulders covered in them. Imagine an area in the Andes mountains, that's what lies in that clearing. I also spotted some claw marks on a tree, so maybe the mountain lions have good taste lol (be careful). Another place I like is atop a hill that might as well be a mini mountain. It has boulders but with red moss, and overlooks the rest of the park. I recommend this place heavily, and it gives me great nostalgia (watch out...