The Old Lower Lighthouse is a disused 19th-century lighthouse on the Isle of Portland, Dorset, southern England. The lighthouse is situated close to the currently functioning Portland Bill Lighthouse, and found along the eastern side of Portland Bill. The lighthouse, including its boundary walls and coastguard house, became Grade II Listed in September 1978.Working alongside the Old Higher Lighthouse from 1716, the lower lighthouse has been rebuilt two times since, once in 1789 and again in 1869. The remaining version of the lighthouse seen today was built in 1869. Since 1961 the lighthouse has been the home of the Portland Bird Observatory.HistoryOriginal operation as a lighthouseThe surrounding coast of Portland, namely Portland Bill and Chesil Beach, have been notorious for the many vessels that became shipwrecked in the area over the centuries. After years of local petitions to Trinity House, the organisation saw a lighthouse at the Bill as being necessary. George I granted Trinity House's patent in 1716.Two lighthouses were built at Portland Bill - one, the Old Higher Lighthouse, at Branscombe Hill, and this one on lower land. The two lighthouses shone out for the first time on 29 September 1716. In 1789, Trinity House hired the Weymouth builder William Johns to demolish and rebuild the lower lighthouse. The new lighthouse, 63 feet high and built of Portland stone, was then installed with a new lens light created by Thomas Rogers. In 1869 Trinity House had both lighthouses rebuilt to allow for better improvements to be made.