The main entrance to Horsethief Lake State Park / Cascade Hills State Park is located in a well marked area approximately 2 (about 3 km) east of The Dalles and highway 14 interchange with US 197. Approximately 1 mile east of that you will encounter a separate paved parking area that is the parking area for the Horsethief Butte trail. Here you will find a few parking spaces, a pit toilet, and the start of the Horsethief Butte trail - or rather trails.
Parking is limited, especially for larger vehicles. Furthermore, there is no good pedestrian access between the two parks, as the bridge over the chasm at Horsthief Lake itself is too narrow for any sort of walkway.
You will find a few signs posted here, including a hand drawn map of the various trails and climbing routes that go to and around Horsethief Butte.
This is a lesser traveled area, especially during the weekdays in the non-peak tourist season, and it is best to watch for snakes. Most of the snakes you will find here are harmless. There are rattlesnakes but for the most part they have left the area frequently used by visitors. The bull snake is more common, but it is harmless, as are a number of other snakes found here.
NOTE: There is a known problem with the door on the restroom at this parking area, and sometimes it gets locked by those leaving the restroom so that the next person can't use it. Your best bet really is to use the restroom at the main part of the park, where the picnic area and camping area is located.
As with the main part of the state park, parking here requires a Discover Pass (see my Discover Pass tip.
BEFORE YOU VIST:
Understand that the pictograph trail is only available by making a reservation with the Washington State Parks department, using the phone number listed on that tip. Tours are only operated Fridays and Saturdays. Be sure to read other material about the tour and park.
Understand that the park closes during November, December, January, February, and March. The exact days of closure are somewhat variable depending on the calendar year, but that is a basic guideline for when the park is open. The hours are 6:30 am to dusk, except for the overnight camping area.
Depends a lot on where you are coming from. The fastest way through the Columbia Gorge is on Interstate 84, but I-84 doesn't allow you to see much. Therefore, many tourists may prefer one of the lesser routes. It depends on what you are doing.
The entrance to the park is on Washington State Route 14. To get there from I-84, take exit 87 and go north on US 197 across the Columbia River until it comes to an end at SR14. Turn right. Going east from 197, the park entrance is approximately 1.5 miles east of the intersection. The entrance is on your right, just as you start to see the Columbia River ahead of you in the distance. There are some signs that identify the park before you get to it, but they are not easy to see. Furthermore, many of the signs now identify the place as "Columbia Hills State Park" rather than the older "Horsethief Lake" name. Several sources state that the entrance to the park is at milepost 85, but I did not notice the mileposts so I can not verify this.
The park road from SR14 to the main part of the park is quite narrow, and be really careful of larger verhicles and/or people going much too fast for the conditions of this road. While the parking lot at the petroglyph area is designed for longer vehicles such as motor homes, the fact is that backing out of those parking places could be a major undertaking if people park too close to you. Therefore, if you are driving a larger vehicle I suggest parking in the picnic and camping area near the boat ramp for getting into Horsethief Lake. The turn around area is fairly large, and should not require that you back up at all - particularly during the off-peak season. To get to this turn around, you need to turn left on the park road that is just past the RV toilet dump facility.
The phone number and web site below are those officially maintained by the Washington State Parks system. The phone number is the one that you need to call for reservations for the pictograph tour, but is also an information number for the park.