-Hammon Grove Park truly offers you an unique experience of 9 holes of disc golf that weave back and forth through the back section of the park. Amenities are pretty decent here, as there are bathrooms and garbage cans near the bottom parking lot, which has more than enough space for cars. There is none, however, throughout the course. This 9-holer loops pretty close back to the bottom parking area.
-The tees are concrete, decent size, and in good shape. They could be slightly longer for my comfort level, but they are very wide at the throwing end and are built nicely into the ground.
-Baskets are Mach 2 and are in good condition, display the hole numbers on them, and were generally easy to spot from the tee (minus 7's blind shot)
-The holes were very fun to play and had a great variance of styles and lines: uphill, downhill, anhyzer, hyzer, open, some with tight lines, over a ravine, etc. Therefore, the course designers put a good effort into giving this course a great variety and used the park to it's maximum potential. The use of elevation deserves special mention, very well utilized within the park's setting.
-Navigation is good and the course flows pretty well. For the not-so-obvious spots, the next tees were never far off so you at least will not be wandering around too much. The course is condensed in one area of the park.
-This course is very raw, but the designers did a good job of making trails throughout the very rugged terrain to make it easier to venture through the park. This was greatly appreciated. There were even some creatively manicured greens on 1 or 2 holes.
-Practice basket on right as you enter the park

-Somewhat hard to find as it's address is 5560 state highway 20 and the road is not marked too well. If heading east about 10-15 minutes passed Marysville, look for an RV park on the left and the park road is shortly after on the right. There is a metal gate with the park sign on it.
-Tee signs are hardly helpful at all, except that they include the hole number and the par (which are all threes anyways). There are no distances and only for a few signs do they have the pin placement and maybe a tree marked. This is strange because it doesn't appear that the signs have faded, just as if they were never completed. No hole lengths on the website makes me assume that they were never determined after 5 years.
-Holes are pretty short for the most part, especially the first five. They do not seem to vary much in distance.
-Multiple rattlesnake-warning signs make it seem like there is a good possibility of seeing one, though we saw no signs of them
-Poison oak in abundance, be cautious before you throw and before you reach for you disc. The amount of poison oak present definitely hurt my enjoyment level.

-The aspect that probably caused me to enjoy this course the most was the truly uniqueness of the holes and the course setting. I struggled with how I felt about this course as I enjoyed the holes in and of themselves - as well as the unique park setting - but there were many grand detractors about the course overall that I noted above.

Holes 1 and 2 are nothing special, and I even would say that I disliked 1. There were many fun holes here though:

5- Plays over a deep and fairly wide ravine. It's a fun placement as it is risky to go for the basket off the tee with the ravine close to it. Plus, it's easy to retrieve your disc from the ravine.
6- Plays through tight lines of trees and shrubs; slighty downhill and then uphill as pin is on a steep slope
7- Slightly downhill launch over short but very thick brush. Pin is through 2 patches of trees
8- Uphill anhyzer that winds through trees

Hammon Grove DGC makes good use of its inherent features. The plentiful elevation changes are used in a variety of ways: 1 is a steep uphill shot, 5 plays next to a pretty drastic ravine (which is graciously playable if your disc ends up down there) and invites a hyzer over open space if you want to push for birdie, 6 drops downward and then works back upward with the pin positioned on the hillside, 7 plays over a broad and gradual downslope, and 8 (as well as 9 to a lesser extent) works gradually uphill. These elevation changes are the course's strong suit, and provide some nice looks.

There are a good variety of hole lengths. It's hard to say without them being marked, but it feels like 275' is the mean, with 3 and 8 likely over 300' and 6 probably above 400'. I appreciated the designer's inclination to stretch and space out the holes in order to maximize how the course used the land.

Tree lines and various copses are used well. I wouldn't classify it as "heavily wooded," having played a lot in Pennsylvania, but 3-6 feature definite lines, some low ceilings, and a few guarded pins, and 7-9 possess some notable obstacles as well (7's tight approach through the trees is nice, and helps make an otherwise-open hole interesting). 1 & 2 are pretty open, especially the latter, but aren't throwaways.

Navigation is relatively easy, and the layout features a nice in and out.

The practice basket at the park's entrance is a nice touch. The course starts a bit further back along the road, when it starts to rise, and seems to be set apart from any non disc golf activities, which I always appreciate.

5 is the standout hole for me: several possible lines with various balances of risk and reward. It's nice to get punished for missing the hyzer route (falling 30'+ down into the small ravine) without risking losing a disc and having the opportunity to redeem yourself if you hit a quality upshot. Both my partner and I landed down here and still managed threes.

In general, I would describe my overall impression of the course as "decent." Harmon Grove is utilitarian in its fulfillment of its role without flash. I didn't come away replaying any shots in my head or otherwise mulling over what the course had presented me, with the possible exception of hole 5; it was in and out. Everyone has their preferences of course, and Harmon Grove is respectably designed, but it didn't grab me.

This may be due to the fact that HG seems to need a little TLC. The course has a rough feel to it, and doesn't seem very well tended. It hasn't been mowed in some time, considering the profusion of knee high-ish dead grass. The tee signs feature minimal information: no distance, and rarely any information about line or pin location. The tees could be a bit longer, which is especially noticeable in the cases where the surrounding terrain doesn't allow for you to initially approach from off the tee pad.

No alternate tees or pins.

Poison Oaks (graciously labeled) are indeed everywhere. There's a fair share of grabby brush and shrubs, making spotters necessary on a few holes (such as 3 and 7).

I enjoyed my round here and would return if I was in the immediate area, but otherwise wouldn't press to come back. It's nice to have a course this close to Yuba City.

I'm generally inclined to rate 9 holers a bit lower, due to their brevity; this course would likely be a bit higher for me were it a full 18.

Little quite area with a decent view.

Takes a while to figure out the course, they do not label it very well. The course is not set up very well to be user friendly, so aim good.