choroplethr requires you to use the naming convention in the "region" column (i.e. all lowercase, full name).

data(state.regions)

References

Taken from http://www.epa.gov/envirofw/html/codes/state.html

Examples

data(state.regions) head(state.regions)
#> region abb fips.numeric fips.character #> 1 alaska AK 2 02 #> 2 alabama AL 1 01 #> 3 arkansas AR 5 05 #> 4 arizona AZ 4 04 #> 5 california CA 6 06 #> 6 colorado CO 8 08