Juniper Dunes Wilderness is a 7,140-acre parcel of BLM wilderness (509/536-1200) is 16 miles northeast of Pasco [1] on Pasco-Kahlotus Road. It contains the six largest remaining western juniper groves in Washington, along with sand dunes that top 120 feet high and are up to 1,200 feet long.
Access to the Juniper Dunes Wilderness is only through private land, so you’ll need to get the permission of local ranchers to reach the dunes, and you may need a 4WD vehicle for the last several miles of road.
There are no trails or drinking water, and summer temperatures often exceed 100°F, so come prepared. The best time to visit is in the spring and fall, when temperatures are more moderate.
Links:
[1] http://www.moon.com/destinations/washington/columbia-gorge-and-wine-country/tri-cities