Millbay, also known as Millbay Docks, is an area of dockland in Plymouth, Devon, England. It lies south of Union Street, between West Hoe in the east and Stonehouse in the west. The area is currently subject to a public-private regeneration creating new homes, business premises, marina, a 1000-pupil school and opening up the waterfront to greater public access.Early historyMill Bay was a natural inlet to the west of the Hoe. It was originally far more extensive than the current docks because it included the "Sourepool" which was a tidal salt-marsh that lay roughly along the line of today's Union Street. The Sourepool was separated from the bay by a narrow neck across which tidal mills were built, probably in the 12th century. These mills were operated by the Priors of Plympton who collected the income from grinding corn. By the mid 15th century, the mills were owned and let by the Corporation of Plymouth; the lease was sold to Francis Drake in 1573. In 1591–92 Drake built six new mills along Drake's Leat that had recently been completed. Around this time the old tidal mills closed and the Sourepool was drained ("made drie for a meadow") in 1592.During the English Civil War, Plymouth declared for Parliament and was the subject of a prolonged Royalist siege between 1642 and 1646. At this time Millbay was the only harbour of Plymouth that was out of reach of the Royalist artillery so it became the sole source of resupply for the town. From the end of the Civil War Millbay reverted to a quiet anchorage with no jetties or port facilities, but in 1756 John Smeaton built a jetty and workyard in the south west corner of the harbour for unloading and working the stone for the third Eddystone Lighthouse. A ten-ton ship, named the Eddystone Boat, was based here and took the worked stones out to the reef.