We camped here the night before going up to the top of Haleakala. For some context, we did a campervan trip round Maui for a week and a half, and this was our third stop after camping in Wanapanapa State Park and then Kipahulu. We spent 2 nights in Kipahulu and then our third at Hosmer Grove, so we really took advantage of the $25 entrance fee that covers 3 nights in Haleakala State Park - I'd recommend definitely checking out both camp sites/sides of Haleakala, as they're both beautiful in their own way! 

Hosmer Grove is just inside the state park lines, and has a large parking lot with approx the same size grassy area. The area is small, but it doesn't seem like it ever gets overcrowded - we shared the campground with about four other groups the night we stayed, and there were only 2 vans camping out. There's pit toilets with sinks, running water and soap to wash up afterwards, as well as a water fountain, picnic tables and grills. 

When people say it's cold up there, it's COLD. Our van was too old to make it up to Hosmer Grove, so we hitchhiked up and brought a 2 person tent for the night. the grassy area to camp on is not completely flat, and unfortunately we chose a spot that was on a bit of an incline and struggled to not slide the whole night - so bewarned to find the right spot to camp on. We were there in June, and by nightfall it got to about 30 degrees (probably dropped even more by midnight). Be prepared with a warm sleeping bag, long sleeves, long pants, socks and maybe a warm hat. The next morning, when we woke up and hitched a ride up to see the sunrise, it was still COLD, and everyone at the top was bundled up - some even wearing winter jackets. 

Also a note: I did a lot of researching ahead of time about the sunrise reservation for Haleakala, since we missed the deadline to get one online. We were pretty worried that we wouldn't be able to see the sunrise since on their website it says that all those who don't have a reservation will be turned away at the top. We ended up getting a ride to the top with a couple who also didn't have a sunrise reservation, and when we got to the top *no one* checked if we had a reservation. We were able to park and watch the sun from the summit. It seems that reservations must be checked at the entrance gate, which is right before Hosmer Grove (some maps seem to make it look like the entrance is after Hosmer, but that's definitely not true. the campground is about a 5 minute drive after you get through the entrance). So a note to the pre-planners: if you don't have a reservation and really want to see that sunrise, camp at Hosmer Grove the night before - as long as you're not trying to enter the park from 3AM-7AM, you'll be fine. Last note on the sunrise - in one of the guidebooks it recommended skipping the summit and going to one of the other lookout points to watch the sunrise where it's way less crowded, and I wished we'd listened. It was overcrowded and noisy, and everyone had their phones out for the hour we were there waiting for the sun to rise. If you want to go a bit off the beaten track, I'd recommend checking out one of those other lookout points. if you don't have a reservation, you'll still need to camp at Hosmer Grove the night before for those, since they're still inside the park's boundaries. And if you're going to camp, might as well hike down into the crater after watching the sunrise!