I drove to Jevnaker and took the road up to Tverrsjøstallen and parked there. The road costs 40kr. From there I followed the blue marked path up to the top. There is a very impressive sign at the bottom marking Svarttjernshøgda as Nordmarka's highest point. It was steep up and then flattened off before going up to the summit. By the time I was nearing the summit it was pouring with rain and there was thunder in the air, so I took a very quick trip up the fire tower to see the view (which was obscured by the rain), and then headed back down following the white path. The white path was more direct to Tverrsjøstallen and included several posts telling about how local forestry. So it was an educational walk too. The white path is a gentler slope, which was easier to walk down as the rain made the trail very muddy and slippy. The walk up and down took about 2 hours. It was a good walk, well worth making time for.