Colnbrook is a village in the Slough district in Berkshire, England. It lies within the historic boundaries of Buckinghamshire, and straddles two distributaries of the Colne, the Colne Brook and Wraysbury River. These two streams have their confluence just to the southeast of the village. Colnbrook is centred 3 miles southeast of the Slough town centre, 4 miles east of Windsor, and 19 miles west of central London. Colnbrook forms the greater part of the civil parish of Colnbrook with Poyle.