Block from U+AC00 to U+D7AF. This block was introduced in Unicode version 2.0 (1996). It contains 11172 codepoints.
The Wikipedia provides the following information on block Hangul Syllables:
Hangul Syllables is a Unicode block containing precomposed Hangul syllable blocks for Modern Korean. The syllables can be directly mapped by algorithm to sequences of characters in the Hangul Jamo Unicode block.