Astwell is a hamlet in Northamptonshire, England. With Falcutt, it is part of the civil parish of Helmdon, but formerly Astwell was split between the parishes of Syresham and Wappenham. The hamlet is 6 miles (10 km) northeast of Brackley and 17+1⁄2 miles (28 km) by road southwest of the county town of Northampton. Today the hamlet contains little more than the Astwell Castle and a mill.