Three river islands (aits) form a linear group, close to the junction of the two main old streets of Thames Ditton village, in the River Thames in a corner of modern Surrey, on the Kingston reach above Teddington Lock. Thames Ditton Island, the dominant ait, is 350 yards (320 m) long and has 48 houses with gardens ; Boyle Farm Island has one house; Swan Island, between the two, is the smallest.