The list is the FIPS codes of District of Columbia counties.
All the FIPS codes are starting with 11.
County
FIPS Code
Washington
11001
All codes are cited from United States Department of Agriculture [28].
Data Source
[28] United States Department of Agriculture. County FIPS Codes. Retrieved October 31, 2020, from https://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/home/?cid=nrcs143_013697