Surname distribution maps for Corwin
Corwin in the 1881 Census
Corwin in the 21st Century
The maps, if available, show both where there are more people named Corwin and where they are most concentrated.
The darker the colour, the more people in that county are named Corwin.
The larger the dot, the greater the proportion of people in that county are named Corwin.
Hovering over the dots will give you the individual statistics for that county.