Dalarwen is located on the shores of Llyn Brianne reservoir at the southernmost edge of the Cambrian Mountains. The nearest towns are Llandovery to the south; Builth Wells and Llandrindod Wells to the east and Tregaron to the north-west.
Approaching Llandovery from the east, continue through Llandovery on the A40. Just before the level crossing turn right. Take the first left (signposted Rhandirmwyn and Llyn Brianne). Continue on this road through Rhandirmwyn village and on past the Dinas Bird Reserve, then take the second left into Llyn Brianne main car park.
Unlock the gate and pass over the dam wall, along the road around the lake for 2.5 miles when Dalarwen will be found down to your right. The entrance lane is then 100 yards further on.