For me Thirlmere is one of the most dramatic of the Cumbrian lakes, despite being partly a reservoir. The long narrow lake runs through a steep sided canyon, with the Hellvelyn range rising dramatically from the eastern bank. Only Hawes Water is higher above sea level.
On my last visit to Thirlmere, in the summer of 2006, the lake was surrounded by free car parks. However, that appears to have changed recently and four of the main car parks are now pay and display. However, the car park by the dam still appears to be free, and is well worth a visit.
Most visitors will pass Thirlmere on the main road between the north and south Lakes. However, the quiet road on the opposite side of the lake is much more interesting, winding dramatically through the trees, with views across to the Hellvelyn range over the lake. Park at Wythburn or Dobgill to climb up to Harrop Tarn and Blea Tarn.