Streatlam Castle was a Baroque stately home located near the town of Barnard Castle in County Durham, England, that was demolished in 1959. Owned by the Bowes-Lyon family, Earls of Strathmore and Kinghorne, the house was one of the family's three principal seats, alongside Glamis Castle in Forfarshire, Scotland, and Gibside, near Gateshead. Streatlam incorporated some 1,190 acres (4.8 km2) of land, along with an estate consisting of some twenty farms. The last occupant was Lord Glamis, who later became the 15th Earl, although the estate was owned by his father, the 14th Earl, at the time.

Barnard Castle is a market town on the north bank of the River Tees, in County Durham, England. The town is named after and built around a medieval castle ruin. The town's Bowes Museum's has an 18th-century Silver Swan automaton exhibit and paintings by Goya and El Greco.