Similarly, the English clan-villages decrease gradually in numbers as we move westward, till they almost disappear beyond the central dividing ridge.

We learn from Domesday Book that at the date of the Norman conquest the number of serfs was greater from east to west, and largest on the Welsh border.
Mr.Isaac Taylor points out that a similar argument may be derived from the area of the hundreds in various counties.

The hundred was originally a body of one hundred English families (more or less), bound together by mutual pledge, and answerable for one another's conduct.

In Sussex, the average number of square miles in each hundred is only twenty-three; in Kent, twenty-four; in Surrey, fifty-eight; and in Herts, seventy-nine: but in Gloucester it is ninety-seven; in Derby, one hundred and sixty-two; in Warwick, one hundred and seventy-nine; and in Lancashire, three hundred and two.

These facts imply that the English population clustered thickest in the old settled east, but grew thinner and thinner towards the Welsh and Cumbrian border.