Poldhu is a small area in south Cornwall, England, UK, situated on the Lizard Peninsula; it comprises Poldhu Point and Poldhu Cove. Poldhu means "black pool" in Cornish. Poldhu lies on the coast of Mount's Bay and is in the northern part of the parish of Mullion; the churchtown is to the south-east. On the north side of Poldhu Cove is the parish of Gunwalloe and the village of Porthleven is a further to the north.
Poldhu Point became the site of one of the main technological advances of the early twentieth century when, on 12 December 1901, a wireless signal was sent to St John’s, Newfoundland, by Marconi. The technology was a precursor to radio, television, satellites and the internet, with the earth station at Goonhilly Downs a nearby example.