Christchurch () is a town and civil parish on the south coast of Dorset, England. The parish had a population of 31,372 in 2021. It adjoins Bournemouth to the west, with the New Forest to the east. Part of the historic county of Hampshire, Christchurch was a borough within the administrative county of Dorset from 1974 until 2019, when it became part of the new Bournemouth, Christchurch and Poole unitary authority.
Founded in the 7th century at the confluence of the rivers Avon and Stour which flow into Christchurch Harbour, the town was originally named Twynham but became known as Christchurch following the construction of the priory in 1094. The town developed into an important trading port, and was fortified in the 9th century. Further defences were added in the 12th century with the construction of a castle, which was destroyed during the English Civil War by the Parliamentarian Army. During the 18th and 19th centuries, smuggling flourished and became one of the town's most lucrative industries. The town was heavily fortified during the Second World War as a precaution against an expected invasion, and in 1940 an Airspeed factory was established on the town's airfield to make aircraft for the Royal Air Force.
The town's harbour, beaches, nature reserves and historically important buildings have made Christchurch a popular tourist destination. Bournemouth Airport, an international airport which handled around 800,000 passengers in 2019, is within the former borough boundary at Hurn. The airport's industrial park contains a number of aerospace and engineering businesses and is one of the largest employment sites in Dorset.