vacanza · arkid15r · Jun 25, 2025 · Jun 5, 2025 · Jun 5, 2025 · Jun 5, 2025
@@ -105,7 +105,7 @@ and detailed information.
 
 ## Available Countries
 
-We currently support 204 country codes. The standard way to refer to a country is by using its [ISO
+We currently support 205 country codes. The standard way to refer to a country is by using its [ISO
 3166-1 alpha-2 code](https://en.wikipedia.org/wiki/List_of_ISO_3166_country_codes), the same used
 for domain names, and for a subdivision its [ISO 3166-2
 code](https://en.wikipedia.org/wiki/ISO_3166-2). Some countries have common or foreign names or
@@ -994,6 +994,13 @@ any) in brackets, available languages and additional holiday categories. All cou
 <td></td>
 </tr>
 <tr>
+<td>Mongolia</td>
+<td>MN</td>
+<td></td>
+<td>en_US, <strong>mn</strong></td>
+<td>WORKDAY</td>
+</tr>
+<tr>
 <td>Montenegro</td>
 <td>ME</td>
 <td></td>

@@ -22,6 +22,7 @@
 from holidays.calendars.islamic import _CustomIslamicHolidays, _IslamicLunar
 from holidays.calendars.julian import JULIAN_CALENDAR
 from holidays.calendars.julian_revised import JULIAN_REVISED_CALENDAR
+from holidays.calendars.mongolian import _CustomMongolianHolidays, _MongolianLunisolar
 from holidays.calendars.persian import _Persian
 from holidays.calendars.sinhala import _SinhalaLunar, _CustomSinhalaHolidays
 from holidays.calendars.thai import _ThaiLunisolar, KHMER_CALENDAR, THAI_CALENDAR
@@ -0,0 +1,342 @@
+#  holidays
+#  --------
+#  A fast, efficient Python library for generating country, province and state
+#  specific sets of holidays on the fly. It aims to make determining whether a
+#  specific date is a holiday as fast and flexible as possible.
+#
+#  Authors: Vacanza Team and individual contributors (see CONTRIBUTORS file)
+#           dr-prodigy <dr.prodigy.github@gmail.com> (c) 2017-2023
+#           ryanss <ryanssdev@icloud.com> (c) 2014-2017
+#  Website: https://github.com/vacanza/holidays
+#  License: MIT (see LICENSE file)
+
+from datetime import date
+from typing import Optional
+
+from holidays.calendars.custom import _CustomCalendar
+from holidays.calendars.gregorian import JAN, FEB, MAR, MAY, JUN, OCT, NOV, DEC
+
+BUDDHA_DAY = "BUDDHA_DAY"
+GENGHIS_KHAN_DAY = "GENGHIS_KHAN_DAY"
+TSAGAAN_SAR = "TSAGAAN_SAR"
+
+
+class _MongolianLunisolar:
+    BUDDHA_DAY_DATES = {
+        2004: (JUN, 3),
+        2005: (MAY, 23),
+        2006: (JUN, 11),
+        2007: (MAY, 31),
+        2008: (MAY, 20),
+        2009: (JUN, 7),
+        2010: (MAY, 27),
+        2011: (MAY, 17),
+        2012: (JUN, 4),
+        2013: (MAY, 25),
+        2014: (JUN, 13),
+        2015: (JUN, 2),
+        2016: (MAY, 21),
+        2017: (JUN, 9),
+        2018: (MAY, 29),
+        2019: (MAY, 18),
+        2020: (JUN, 5),
+        2021: (MAY, 26),
+        2022: (JUN, 14),
+        2023: (JUN, 4),
+        2024: (MAY, 23),
+        2025: (JUN, 11),
+        2026: (MAY, 31),
+        2027: (MAY, 20),
+        2028: (JUN, 7),
+        2029: (MAY, 27),
+        2030: (MAY, 17),
+        2031: (JUN, 5),
+        2032: (MAY, 25),
+        2033: (JUN, 12),
+        2034: (JUN, 2),
+        2035: (MAY, 22),
+        2036: (JUN, 8),
+        2037: (MAY, 29),
+        2038: (MAY, 18),
+        2039: (JUN, 6),
+        2040: (MAY, 26),
+        2041: (JUN, 14),
+        2042: (JUN, 3),
+        2043: (MAY, 23),
+        2044: (JUN, 10),
+        2045: (MAY, 30),
+        2046: (MAY, 20),
+        2047: (JUN, 8),
+        2048: (MAY, 27),
+        2049: (MAY, 17),
+        2050: (JUN, 5),
+        2051: (MAY, 25),
+        2052: (JUN, 12),
+        2053: (JUN, 1),
+        2054: (MAY, 21),
+        2055: (JUN, 9),
+        2056: (MAY, 29),
+        2057: (MAY, 18),
+        2058: (JUN, 6),
+        2059: (MAY, 27),
+        2060: (JUN, 14),
+        2061: (JUN, 3),
+        2062: (MAY, 23),
+        2063: (JUN, 11),
+        2064: (MAY, 30),
+        2065: (MAY, 20),
+        2066: (JUN, 8),
+        2067: (MAY, 28),
+        2068: (JUN, 15),
+        2069: (JUN, 4),
+        2070: (MAY, 24),
+        2071: (JUN, 12),
+        2072: (MAY, 31),
+        2073: (MAY, 21),
+        2074: (JUN, 9),
+        2075: (MAY, 30),
+        2076: (MAY, 18),
+        2077: (JUN, 6),
+        2078: (MAY, 26),
+        2079: (JUN, 14),
+        2080: (JUN, 2),
+        2081: (MAY, 22),
+        2082: (JUN, 10),
+        2083: (MAY, 31),
+        2084: (MAY, 20),
+        2085: (JUN, 8),
+        2086: (MAY, 28),
+        2087: (JUN, 16),
+        2088: (JUN, 4),
+        2089: (MAY, 24),
+        2090: (JUN, 12),
+        2091: (JUN, 1),
+        2092: (MAY, 21),
+        2093: (JUN, 9),
+        2094: (MAY, 30),
+        2095: (MAY, 19),
+        2096: (JUN, 6),
+        2097: (MAY, 26),
+        2098: (JUN, 13),
+        2099: (JUN, 3),
+        2100: (MAY, 23),
+    }
+
+    GENGHIS_KHAN_DAY_DATES = {
+        2004: (NOV, 13),
+        2005: (NOV, 2),
+        2006: (NOV, 21),
+        2007: (NOV, 10),
+        2008: (NOV, 28),
+        2009: (NOV, 17),
+        2010: (NOV, 7),
+        2011: (NOV, 26),
+        2012: (NOV, 14),
+        2013: (NOV, 4),
+        2014: (NOV, 23),
+        2015: (NOV, 12),
+        2016: (OCT, 31),
+        2017: (NOV, 19),
+        2018: (NOV, 8),
+        2019: (NOV, 27),
+        2020: (NOV, 16),
+        2021: (NOV, 5),
+        2022: (NOV, 24),
+        2023: (NOV, 14),
+        2024: (NOV, 2),
+        2025: (NOV, 21),
+        2026: (NOV, 10),
+        2027: (NOV, 29),
+        2028: (NOV, 17),
+        2029: (NOV, 7),
+        2030: (NOV, 26),
+        2031: (NOV, 15),
+        2032: (NOV, 4),
+        2033: (NOV, 22),
+        2034: (NOV, 11),
+        2035: (NOV, 30),
+        2036: (NOV, 18),
+        2037: (NOV, 8),
+        2038: (NOV, 27),
+        2039: (NOV, 17),
+        2040: (NOV, 5),
+        2041: (NOV, 24),
+        2042: (NOV, 13),
+        2043: (NOV, 2),
+        2044: (NOV, 20),
+        2045: (NOV, 9),
+        2046: (NOV, 28),
+        2047: (NOV, 18),
+        2048: (NOV, 7),
+        2049: (NOV, 26),
+        2050: (NOV, 15),
+        2051: (NOV, 4),
+        2052: (NOV, 22),
+        2053: (NOV, 11),
+        2054: (NOV, 30),
+        2055: (NOV, 19),
+        2056: (NOV, 8),
+        2057: (NOV, 27),
+        2058: (NOV, 17),
+        2059: (NOV, 6),
+        2060: (NOV, 24),
+        2061: (NOV, 13),
+        2062: (NOV, 2),
+        2063: (NOV, 21),
+        2064: (NOV, 9),
+        2065: (NOV, 28),
+        2066: (NOV, 18),
+        2067: (NOV, 7),
+        2068: (NOV, 25),
+        2069: (NOV, 14),
+        2070: (NOV, 3),
+        2071: (NOV, 22),
+        2072: (NOV, 11),
+        2073: (NOV, 30),
+        2074: (NOV, 19),
+        2075: (NOV, 9),
+        2076: (NOV, 27),
+        2077: (NOV, 16),
+        2078: (NOV, 5),
+        2079: (NOV, 24),
+        2080: (NOV, 12),
+        2081: (NOV, 1),
+        2082: (NOV, 21),
+        2083: (NOV, 10),
+        2084: (NOV, 28),
+        2085: (NOV, 18),
+        2086: (NOV, 7),
+        2087: (NOV, 26),
+        2088: (NOV, 14),
+        2089: (NOV, 3),
+        2090: (NOV, 22),
+        2091: (NOV, 12),
+        2092: (NOV, 30),
+        2093: (NOV, 19),
+        2094: (NOV, 9),
+        2095: (NOV, 27),
+        2096: (NOV, 15),
+        2097: (NOV, 5),
+        2098: (NOV, 23),
+        2099: (NOV, 13),
+        2100: (DEC, 2),
+    }
+
+    TSAGAAN_SAR_DATES = {
+        2004: (FEB, 21),
+        2005: (FEB, 9),
+        2006: (JAN, 30),
+        2007: (FEB, 18),
+        2008: (FEB, 8),
+        2009: (FEB, 25),
+        2010: (FEB, 14),
+        2011: (FEB, 3),
+        2012: (FEB, 22),
+        2013: (FEB, 11),
+        2014: (JAN, 31),
+        2015: (FEB, 19),
+        2016: (FEB, 9),
+        2017: (FEB, 27),
+        2018: (FEB, 16),
+        2019: (FEB, 5),
+        2020: (FEB, 24),
+        2021: (FEB, 12),
+        2022: (FEB, 2),
+        2023: (FEB, 21),
+        2024: (FEB, 10),
+        2025: (MAR, 1),
+        2026: (FEB, 18),
+        2027: (FEB, 7),
+        2028: (FEB, 26),
+        2029: (FEB, 14),
+        2030: (FEB, 3),
+        2031: (FEB, 22),
+        2032: (FEB, 12),
+        2033: (JAN, 31),
+        2034: (FEB, 19),
+        2035: (FEB, 9),
+        2036: (FEB, 28),
+        2037: (FEB, 16),
+        2038: (FEB, 5),
+        2039: (FEB, 24),
+        2040: (FEB, 13),
+        2041: (FEB, 2),
+        2042: (FEB, 21),
+        2043: (FEB, 10),
+        2044: (FEB, 29),
+        2045: (FEB, 17),
+        2046: (FEB, 6),
+        2047: (FEB, 25),
+        2048: (FEB, 14),
+        2049: (FEB, 3),
+        2050: (FEB, 22),
+        2051: (FEB, 12),
+        2052: (FEB, 1),
+        2053: (FEB, 19),
+        2054: (FEB, 8),
+        2055: (FEB, 27),
+        2056: (FEB, 16),
+        2057: (FEB, 4),
+        2058: (FEB, 23),
+        2059: (FEB, 13),
+        2060: (FEB, 3),
+        2061: (FEB, 21),
+        2062: (FEB, 10),
+        2063: (MAR, 1),
+        2064: (FEB, 18),
+        2065: (FEB, 6),
+        2066: (FEB, 25),
+        2067: (FEB, 14),
+        2068: (FEB, 4),
+        2069: (FEB, 22),
+        2070: (FEB, 12),
+        2071: (FEB, 1),
+        2072: (FEB, 19),
+        2073: (FEB, 7),
+        2074: (FEB, 26),
+        2075: (FEB, 16),
+        2076: (FEB, 5),
+        2077: (FEB, 23),
+        2078: (FEB, 13),
+        2079: (FEB, 2),
+        2080: (FEB, 21),
+        2081: (FEB, 9),
+        2082: (FEB, 28),
+        2083: (FEB, 17),
+        2084: (FEB, 7),
+        2085: (FEB, 25),
+        2086: (FEB, 14),
+        2087: (FEB, 4),
+        2088: (FEB, 23),
+        2089: (FEB, 11),
+        2090: (MAR, 2),
+        2091: (FEB, 19),
+        2092: (FEB, 8),
+        2093: (FEB, 26),
+        2094: (FEB, 16),
+        2095: (FEB, 5),
+        2096: (FEB, 24),
+        2097: (FEB, 13),
+        2098: (FEB, 2),
+        2099: (FEB, 21),
+        2100: (FEB, 10),
+    }
+
+    def _get_holiday(self, holiday: str, year: int) -> tuple[Optional[date], bool]:
+        estimated_dates = getattr(self, f"{holiday}_DATES", {})
+        exact_dates = getattr(self, f"{holiday}_DATES_{_CustomCalendar.CUSTOM_ATTR_POSTFIX}", {})
+        dt = exact_dates.get(year, estimated_dates.get(year, ()))
+        return date(year, *dt) if dt else None, year not in exact_dates
+
+    def buddha_day_date(self, year: int) -> tuple[Optional[date], bool]:
+        return self._get_holiday(BUDDHA_DAY, year)
+
+    def genghis_khan_day_date(self, year: int) -> tuple[Optional[date], bool]:
+        return self._get_holiday(GENGHIS_KHAN_DAY, year)
+
+    def tsagaan_sar_date(self, year: int) -> tuple[Optional[date], bool]:
+        return self._get_holiday(TSAGAAN_SAR, year)
+
+
+class _CustomMongolianHolidays(_CustomCalendar, _MongolianLunisolar):
+    pass
@@ -138,6 +138,7 @@
 from holidays.countries.micronesia import Micronesia, FM, FSM
 from holidays.countries.moldova import Moldova, MD, MDA
 from holidays.countries.monaco import Monaco, MC, MCO
+from holidays.countries.mongolia import Mongolia, MN, MNG
 from holidays.countries.montenegro import Montenegro, ME, MNE
 from holidays.countries.morocco import Morocco, MA, MOR
 from holidays.countries.mozambique import Mozambique, MZ, MOZ