The village sits on a hill overlooking Strangford Lough. The nearby settlement of Balloo is treated as part of Killinchy. Sketrick Castle is located near Killinchy and is estimated to date back to the 15th century. The Annals of the Four Masters record the capture of the castle in 1470. It was intact until the end of the 19th century when a storm demolished much of it. In 1957 a stone subterranean passage was discovered.
Killinchy has a community hall and a children's playground. Killinchy has three Churches, Killinchy Presbyterian Church, Killinchy Non-Subscribing Presbyterian Church and Killinchy Church of Ireland. In 1978 a new Church Hall, car park and playing fields were built, on the opposite side of the road, to complement the Anderson Memorial Hall (built 1898). The Moore Graveyard sits at the top of the car park.