The Regional Indicator Symbols are a set of 26 alphabetic characters (A-Z) in the Universal Character Set

Universal Character Set

The Universal Character Set , defined by the International Standard ISO/IEC 10646, Information technology — Universal multiple-octet coded character set , is a standard set of characters upon which many character encodings are based...

 intended to be used to encode ISO 3166-1 alpha-2

ISO 3166-1 alpha-2

ISO 3166-1 alpha-2 codes are two-letter country codes defined in ISO 3166-1, part of the ISO 3166 standard published by the International Organization for Standardization , to represent countries, dependent territories, and special areas of geographical interest...

 two-letter country code

Country code

Country codes are short alphabetic or numeric geographical codes developed to represent countries and dependent areas, for use in data processing and communications. Several different systems have been developed to do this. The best known of these is ISO 3166-1...

s in a way that allows optional special treatment.

These were defined as part of the Unicode 6.0 support for emoji

Emoji

is the Japanese term for the picture characters or emoticons used in Japanese electronic messages and webpages. Originally meaning pictograph, the word literally means e "picture" + moji "letter". The characters are used much like emoticons elsewhere, but a wider range is provided, and the icons...

, as an alternative to encoding separate characters for each country flag. Although they can be displayed as Roman letters, it is intended that implementations may choose to display them in other ways, such as by using national flag

National flag

A national flag is a flag that symbolizes a country. The flag is flown by the government, but usually can also be flown by citizens of the country.Both public and private buildings such as schools and courthouses may fly the national flag...

s.

They are encoded in the range to within the Enclosed Alphanumeric Supplement

Enclosed Alphanumeric Supplement

The Enclosed Alphanumeric Supplement is a Unicode block consisting mostly of Latin alphabet characters enclosed in circles, ovals or boxes, used for a variety of purposes. It is encoded in the range U+1F100 - U+1F1FF in the Supplementary Multilingual Plane....

 block in the Supplementary Multilingual Plane.