The Black Hills are a region and a low mountain range in southwestern South Dakota. This is definitely the main tourist draw in South Dakota. We based ourselves in Hill City while in the Black Hills. Not far from Hill City is this view of Harney Peak - the highest mountain in South Dakota. It's a reasonable day hike up to that tower although we did not attempt it with a two-year old in tow.
There are a wealth of National Parks units in the Black Hills. Two of them (Jewel Cave and Wind Cave) are primarily underground. We weren't entirely sure how Alaric would handle a cave trip so we did the 15 minute tour at Jewel Cave (pictured here). Basically you go down to the first platform and get a fairly generic cave talk. I wouldn't recommend this particular tour for anyone unless they have small children or physical limitations that would make the hour tour problematic.
Jewel Cave gets its name from calcite formations like this one. There is an intriguing map in the visitor center that shows how extensive the Jewel Cave system is. It does not have a known connection to Wind Cave (at this time) but it seems like one may well be discovered in the near future. Visit Jewel Cave primarily for the underground part. There's very little above ground to do here.
Wind Cave National Park on the other hand has a huge expanse which is home to bison, pronghorn antelope and bighorn sheep (among other things).
We skipped the underground portion of Wind Cave entirely but the wildlife loops are worth a visit and there are several trails through the area as well. The assorted specks in this photo are bison.
Wind Cave sort of merges into Custer State Park to the north. Most of the animals probably don't care about this but the buffalo herds are somewhat managed so there are fences and cattle crossings. If you aren't sure where the bison herd is, just drive until you see all the stopped traffic.
Back in Hill City, the prime attraction is the 1880 Train. A restored steam train that makes a short round trip circuit to Keystone and back. We would probably have skipped this if we didn't have a train-obsessed child with us. Since we did have a train-obsessed child with us, we took the ride and it was actually a very pleasant journey. There's a good chance of seeing wildlife (mostly mule deer) and it's a relaxing trip through part of the Black Hills.
Custer State Park occupies a huge section of the Black Hills. Lake Sylvan (shown here) is one of the centerpiece attractions of the State Park. There is a short loop trail here that circumnavigates the lake. There is also a trailhead to access Harney Peak from here.
Sylvan Lake has some unusual rock formations and some fun perspectives, like this one. The lake trail actually goes through a crevice in these rocks and passes behind the rock wall before emerging up on top of them back near the lake.
Just east of the Lake Sylvan area are the Needles which is a very heavily photographed section of crazy rock spires. The road passes through several narrow winding sections among them. Add assorted mules wandering up and down the road and this becomes a very congested area to drive in. If you're wondering - yes, that is a climber on top of that spire.
Custer State Park offers one of the more unique approaches to Mount Rushmore. This is actually a view directly at the carved portion of Mount Rushmore from many miles away.
A more dramatic view is afforded (twice) coming out of the tunnels on the way to Mount Rushmore. This is a scenic highway to start with but the tunnel sections make it particularly special.
Needless to say, we visited Mount Rushmore along with probably everyone else who has ever come within an hour's drive of it. There's a very nice visitor center, gift shop and long promenade with all the US state flags leading from the parking lots to the overlook. Melanie had been here once before in 1993 when there was basically one small parking lot and a platform to stand on. Now it's a bit like you've arrived at a theme park.