Lava Beds National Monument is very remote, and there is no gas available at the park. The nearest gas station may be over an hour away from the monument, so make sure you fill up at one of the nearby cities such as Klamath Falls, Merrill, Tulelake or Alturas.
While you're driving into Lava Beds, keep an eye out for brown highway signs. These mark the turns leading into Lava Beds from US 161.
If you're driving in from Klamath Falls, you'll take Hwy 39 about 15 miles south. Turn right onto Merrill Pit Road, and drive about two miles until you get to Stateline Road 161. Turn left and head east on 161. Turn right onto Hill Road, and it will take you into Lava Beds. You'll pass the Klamath Basin National Wildlife Refuge Visitor Center on your way in. Keep on going, and you'll get to the Lava Beds Visitor Center.
There are a few other ways to get into Lava Beds National Monument. If you're coming in from Redding, you'll have to take Forest Service road 10. Although this road is paved, it has potholes, so make sure you're driving carefully on this route. Additionally, this road is not plowed in the winter, so make sure you choose an alternate route depending on your season of travel.
If you're heading from California Hwy 89 and want to enter the park from the south, make sure your vehicle is prepared for about ten miles of dirt road. The road is technically accessible in any vehicle, but by mid-summer, it will be a much rougher drive due to usage. Plan for about two hours to get into the park if you head this way.