CountryCodes

All countries and subdivisions based on ISO 3166

Usage

List all countries and subdivisions

foreach (var country in Country.GetAllCountries())
{
    Console.WriteLine(country); // Two-letter code (e.g. "US")
    Console.WriteLine(country.Name);
    Console.WriteLine(country.TwoLetterCode); 
    Console.WriteLine(country.ThreeLetterCode);
    Console.WriteLine(country.NumericCode);

    foreach (var subdivision in country.Subdivisions)
    {
        Console.WriteLine(subdivision); // Subdivision code (e.g. "US-AL" for Alabama)
        Console.WriteLine(subdivision.Name);
        Console.WriteLine(subdivision.Code);
    }
}

Static fields

_ = Country.US.Name;                 // "United States"
_ = Country.US.TwoLetterCode;        // "US"
_ = Country.US.ThreeLetterCode;      // "USA"
_ = Country.US.NumericCode;          // 840

foreach (var item in Country.US.Subdivisions)
{
    _ = item.Code;                   // Code for state (e.g. "US-AL")
    _ = item.Name;                   // State name (e.g. "Alabama")
}

Using the constructors

_ = new Country("US") == Country.US;        // true
_ = new Country(840) == Country.US;         // true
_ = new Country("US") == new Country(840);  // true
_ = new Country("XX")                       // ArgumentException

var alabama = new Subdivision("US-AL");
Console.WriteLine(alabama.Name); // "Alabama"
Console.WriteLine(alabama.Code); // "US-AL"

Economic zones

Countries grouped by economic, customs, monetary or free-movement arrangement. Unlike the ISO 3166 data above this is not a standard — membership is political and changes, so it records when it was last verified.

_ = EconomicZone.EU.Code;                   // "EU"
_ = EconomicZone.EU.Name;                   // "European Union"
_ = EconomicZone.EU.Type;                   // EconomicZoneType.EconomicUnion
_ = EconomicZone.EU.Members.Count;          // 27

_ = EconomicZone.EU.Contains(Country.BG);   // true
_ = EconomicZone.EU.Contains(Country.GB);   // false

_ = Country.BE.IsIn(EconomicZone.EU);       // true
_ = Country.DE.Zones;                       // EU, EA, EEA, SCHENGEN, G7

foreach (var zone in EconomicZone.GetAllZones())
{
    Console.WriteLine(zone);                // Code (e.g. "EU")
    Console.WriteLine(zone.Name);
    Console.WriteLine(zone.Type);

    foreach (var country in zone.Members)
        Console.WriteLine(country.Name);
}

_ = new EconomicZone("EU") == EconomicZone.EU;   // true
_ = new EconomicZone("eu") == EconomicZone.EU;   // true, case-insensitive
_ = new EconomicZone("XX");                      // ArgumentException

EconomicZone.TryParse("EEA", out var zone);      // true
EconomicZone.TryParse("XX", out _);              // false

Code	Zone	Type	Members
EU	European Union	EconomicUnion	27
EA	Euro area	MonetaryUnion	21
EEA	European Economic Area	SingleMarket	30
EFTA	European Free Trade Association	FreeTradeArea	4
SCHENGEN	Schengen Area	FreeMovementArea	29
USMCA	United States-Mexico-Canada Agreement	FreeTradeArea	3
GCC	Gulf Cooperation Council	CustomsUnion	6
G7	Group of Seven	GlobalEconomicGroup	7

The zones overlap but are not interchangeable, which is what Type is for. Ireland and Cyprus are in the EU but not Schengen; Switzerland is in Schengen and EFTA but in neither the EU nor the EEA; Sweden and Poland are in the EU but not the euro area.

Zones are modelled at country granularity. Some real arrangements are not: the EU VAT area and the EU customs territory exclude parts of member states (the Canary Islands, Büsingen) and include Monaco. Those are deliberately absent rather than approximated, because a country-level answer to a territory-level question is wrong in exactly the cases that matter.

Benchmarks

BenchmarkDotNet v0.15.8, Windows 11 (10.0.26200.9168/25H2/2025Update/HudsonValley2)
13th Gen Intel Core i7-13700 2.10GHz, 1 CPU, 24 logical and 16 physical cores
.NET SDK 10.0.400
[Host] : .NET 10.0.11 (10.0.11, 10.0.1126.37416), X64 RyuJIT x86-64-v3
DefaultJob : .NET 10.0.11 (10.0.11, 10.0.1126.37416), X64 RyuJIT x86-64-v3

Resolving countries and zones in a loop.

Method	N	Mean	Error	StdDev	Allocated
CountryById	1000	2,204.5 ns	19.85 ns	18.57 ns	-
CountryByCode	1000	42,866.1 ns	115.47 ns	102.36 ns	-
CountryStaticFieldAccess	1000	217.8 ns	1.12 ns	1.05 ns	-
ZoneByCode	1000	3,692.2 ns	12.59 ns	11.77 ns	-
ZoneStaticFieldAccess	1000	1,051.7 ns	2.62 ns	2.32 ns	-
CountryById	10000	22,692.7 ns	141.70 ns	132.55 ns	-
CountryByCode	10000	412,547.7 ns	1,824.02 ns	1,706.19 ns	-
CountryStaticFieldAccess	10000	2,235.8 ns	22.45 ns	21.00 ns	-
ZoneByCode	10000	39,330.5 ns	243.17 ns	215.56 ns	-
ZoneStaticFieldAccess	10000	11,127.5 ns	36.25 ns	32.13 ns	-
CountryById	100000	223,621.2 ns	842.98 ns	703.93 ns	-
CountryByCode	100000	4,141,862.0 ns	28,578.02 ns	26,731.90 ns	-
CountryStaticFieldAccess	100000	21,123.5 ns	193.63 ns	181.12 ns	-
ZoneByCode	100000	369,808.6 ns	1,478.17 ns	1,310.36 ns	-
ZoneStaticFieldAccess	100000	111,204.0 ns	220.44 ns	195.42 ns	-
CountryById	1000000	2,226,817.5 ns	22,132.40 ns	20,702.66 ns	-
CountryByCode	1000000	41,227,199.0 ns	201,475.64 ns	188,460.44 ns	-
CountryStaticFieldAccess	1000000	211,621.3 ns	1,230.15 ns	1,150.68 ns	-
ZoneByCode	1000000	3,793,016.7 ns	10,533.43 ns	9,852.98 ns	-
ZoneStaticFieldAccess	1000000	1,017,915.4 ns	4,091.26 ns	3,826.97 ns	-

Single operations on an already-resolved country or zone.

Method	Mean	Error	StdDev	Median	Gen0	Allocated
CountryEqualsTrue	0.0033 ns	0.0032 ns	0.0030 ns	0.0032 ns	-	-
CountryEqualsTrueNew	75.0247 ns	0.4382 ns	0.4099 ns	75.0421 ns	-	-
CountryEqualsFalse	0.0032 ns	0.0060 ns	0.0056 ns	0.0000 ns	-	-
CountryEqualsFalseNew	269.5699 ns	1.1699 ns	0.9769 ns	269.5760 ns	-	-
ZoneEqualsTrue	0.0078 ns	0.0044 ns	0.0041 ns	0.0073 ns	-	-
ZoneEqualsTrueNew	5.8948 ns	0.0333 ns	0.0312 ns	5.8826 ns	-	-
ZoneEqualsFalse	0.0031 ns	0.0040 ns	0.0038 ns	0.0019 ns	-	-
ZoneEqualsFalseNew	6.6737 ns	0.0385 ns	0.0341 ns	6.6685 ns	-	-
ZoneContainsTrue	2.7037 ns	0.0276 ns	0.0245 ns	2.7003 ns	-	-
ZoneContainsFalse	2.5982 ns	0.0321 ns	0.0300 ns	2.5888 ns	-	-
CountryIsIn	2.7349 ns	0.0234 ns	0.0219 ns	2.7311 ns	-	-
ZoneName	1.7038 ns	0.0323 ns	0.0302 ns	1.6876 ns	-	-
CountryZones	9.5497 ns	0.1309 ns	0.1225 ns	9.5113 ns	0.0020	32 B