The topic of hidden gem is always difficult to address because the definition itself is entirely dependent on what you consider hidden. I found this site because I played a "hidden gem" in Pasatiempo and discovered more about another "hidden gem" named Rustic Canyon on this site. The internet has made the world smaller but our passion for golf course architecture and ability to eloquently share why a course is good or not has diminished the number of courses that fit this category. With that in mind, I'm introducing two courses which I feel do not get discussion on either this site or in the general golf community. They are not courses I would recommend traveling to get to, but if in the area, should be considered for rounds.
Contra Costa CC (Pleasant Hill, CA) - Robert Trent Jones II
Full disclosure: I worked as an intern on the renovation here in 2014 by RTJII and my father is a member of the club. That being said, the club was an 18 hole AV Macan design, they only built 9 of Macan's holes (roughly where the front 9 is today) and then expanded to 18 in the 50's. In spite of Macan's lack of influence, the back is solid, with the highlight being the two-shot 11th, with a green that can play differently depending on the days pin location. That being said, the bread and butter of the course exists on the front. Macan had a par 3 where the green sat in the base of one of the barranca's, and while that has been lost, the 3rd is a stellar 4.5 par hole, with a shallow green and bunkering which mimics that of MacKenzie's work, the 5th, a short one-shotter with a reverse redan green, and the 6th, which, not including SFGC and Cal Club (since I have not seen either), is the best Par 5 I have seen in the Bay Area. Those hoping to reach the green in two have to hit a right-to-left shot that sneaks by the fairway bunker guarding the right, and then face an approach to a green which is guarded on the left by a greenside bunker and a barranca. Those laying up play a shot down to the valley 20-30 ft below, where they face a semi-blind approach up the hill to the green.
I always felt that Contra had the bones to be a great golf course, but it fell victim to a greens committee that had put in features which had no place on the golf course, and so much of it felt built up in spite of the routing. The focus of the renovation was to make the golf course feel like it fit into the landscape, much like Poppy Hill's renovation focused on getting rid of the most artificial of features. I still think there is some enlightenment to be had with the greens committee, the most egregious decision I saw during the redo was the greens committee's decision to keep a hawthorne tree, hardly a specimen, on the right of the 14th green, in spite of the fact that it diminished the playing characteristics of the hole AND blocked the view of Mt. Diablo on the 15th tee, but the redo by RTJII was terrific, and it was a great project to work on.
(on a side note, anyone wanting to see Contra Costa should send me a message. No promises as my dad, newly retired, travels quite a bit, but he's happy to show people around if I'm not in town)
Balboa Park (San Diego, CA) - William Bell
I am incredibly lucky to have lived the last 5 months less than a mile from Balboa, a William Bell design that opened in 1921. Admittedly, when I moved down here, my expectation was to take advantage of the local rates at Torrey, pop over to Barona every once in a while (which, I've been popping over to Barona much more during the week as their twilight rates are quite good, but that's beside the point). It just so happened that the first round I played down here was at Balboa, and in spite of it's short 6000 yard back tees, I was blown away. It's full of quirky, interesting holes, most notably the bunkerless 4th, where you play an iron off the tee and face a mid-length approach to a green benched into the hillside, but anything missed right of the green faces a brutally daunting up and down from well below the green.
However, what blows me away about Balboa isn't the wealth of half par holes or the quirky holes on the golf course, it's how well the routing takes advantage of the bluffs of the canyons and the valley. The first 5 holes work through the valley below, with the long par-3 6th creating the transition up to the top of the canyon, and while the 8th through 10th are rather bland golf holes, the rest of the back 9 works out on the fingers of the bluffs above the first 6th, reaching a climax with the par 5 16th, a dogleg left with a lateral hazard (the canyon) on the left and OB (property line and the end of the ridge) on the right. The hole features some of the best views of downtown San Diego and is downright thrilling. Other than Clear Creek (which uses the terrain to add length to the course to mitigate the altitude) it is one of the most ingenious routings I have ever seen, and a terrific use of space.