diff --git a/src/World.Net.UnitTests/Countries/JamaicaTest.cs b/src/World.Net.UnitTests/Countries/JamaicaTest.cs
new file mode 100644
index 0000000..67439db
--- /dev/null
+++ b/src/World.Net.UnitTests/Countries/JamaicaTest.cs
@@ -0,0 +1,39 @@
+namespace World.Net.UnitTests.Countries;
+public sealed class JamaicaTest
+{
+    private const string JAMAICA_COUNTRY_NAME = "Jamaica";
+    private const string JAMAICA_NATIVE_NAME = "Jamaica";
+    private const string JAMAICA_CAPITAL = "Kingston";
+    private const string JAMAICA_OFFICIAL_NAME = "Jamaica";
+    private const string JAMAICA_ISO2_CODE = "JM";
+    private const string JAMAICA_ISO3_CODE = "JAM";
+    private const int JAMAICA_NUMERIC_CODE = 388;
+    private readonly string[] JAMAICA_CALLING_CODE = ["+1-876"];
+    private const int JAMAICA_STATE_COUNT = 14;
+    private static readonly string[] VALID_STATE_TYPES = { "Parish" };
+
+    [Fact]
+    public void GetCountry_ReturnsCorrectInformation_ForJamaica()
+    {
+        // Arrange
+        CountryIdentifier existingCountryId = CountryIdentifier.Jamaica;
+
+        // Act
+        var country = CountryProvider.GetCountry(existingCountryId);
+
+        // Assert
+        Assert.NotNull(country);
+        Assert.Equal(existingCountryId, country.Id);
+        Assert.Equal(JAMAICA_COUNTRY_NAME, country.Name);
+        Assert.Equal(JAMAICA_OFFICIAL_NAME, country.OfficialName);
+        Assert.Equal(JAMAICA_NATIVE_NAME, country.NativeName);
+        Assert.Equal(JAMAICA_CAPITAL, country.Capital);
+        Assert.Equal(JAMAICA_NUMERIC_CODE, country.NumericCode);
+        Assert.Equal(JAMAICA_ISO2_CODE, country.ISO2Code);
+        Assert.Equal(JAMAICA_ISO3_CODE, country.ISO3Code);
+        Assert.Equal(JAMAICA_CALLING_CODE, country.CallingCode);
+        Assert.NotNull(country.States);
+        Assert.Equal(JAMAICA_STATE_COUNT, country.States.Count());
+        Assert.All(country.States, state => Assert.Contains(state.Type, VALID_STATE_TYPES));
+    }
+}
diff --git a/src/World.Net.UnitTests/Countries/JapanTest.cs b/src/World.Net.UnitTests/Countries/JapanTest.cs
new file mode 100644
index 0000000..ef974b9
--- /dev/null
+++ b/src/World.Net.UnitTests/Countries/JapanTest.cs
@@ -0,0 +1,39 @@
+namespace World.Net.UnitTests.Countries;
+public sealed class JapanTest
+{
+    private const string JAPAN_COUNTRY_NAME = "Japan";
+    private const string JAPAN_NATIVE_NAME = "日本";
+    private const string JAPAN_CAPITAL = "Tokyo";
+    private const string JAPAN_OFFICIAL_NAME = "Japan";
+    private const string JAPAN_ISO2_CODE = "JP";
+    private const string JAPAN_ISO3_CODE = "JPN";
+    private const int JAPAN_NUMERIC_CODE = 392;
+    private readonly string[] JAPAN_CALLING_CODE = ["+81"];
+    private const int JAPAN_STATE_COUNT = 47;
+    private static readonly string[] VALID_STATE_TYPES = { "Prefecture" };
+
+    [Fact]
+    public void GetCountry_ReturnsCorrectInformation_ForJapan()
+    {
+        // Arrange
+        CountryIdentifier existingCountryId = CountryIdentifier.Japan;
+
+        // Act
+        var country = CountryProvider.GetCountry(existingCountryId);
+
+        // Assert
+        Assert.NotNull(country);
+        Assert.Equal(existingCountryId, country.Id);
+        Assert.Equal(JAPAN_COUNTRY_NAME, country.Name);
+        Assert.Equal(JAPAN_OFFICIAL_NAME, country.OfficialName);
+        Assert.Equal(JAPAN_NATIVE_NAME, country.NativeName);
+        Assert.Equal(JAPAN_CAPITAL, country.Capital);
+        Assert.Equal(JAPAN_NUMERIC_CODE, country.NumericCode);
+        Assert.Equal(JAPAN_ISO2_CODE, country.ISO2Code);
+        Assert.Equal(JAPAN_ISO3_CODE, country.ISO3Code);
+        Assert.Equal(JAPAN_CALLING_CODE, country.CallingCode);
+        Assert.NotNull(country.States);
+        Assert.Equal(JAPAN_STATE_COUNT, country.States.Count());
+        Assert.All(country.States, state => Assert.Contains(state.Type, VALID_STATE_TYPES));
+    }
+}
diff --git a/src/World.Net.UnitTests/Countries/JerseyTest.cs b/src/World.Net.UnitTests/Countries/JerseyTest.cs
new file mode 100644
index 0000000..fad36bd
--- /dev/null
+++ b/src/World.Net.UnitTests/Countries/JerseyTest.cs
@@ -0,0 +1,39 @@
+namespace World.Net.UnitTests.Countries;
+public sealed class JerseyTest
+{
+    private const string JERSEY_COUNTRY_NAME = "Jersey";
+    private const string JERSEY_NATIVE_NAME = "Jersey";
+    private const string JERSEY_CAPITAL = "Saint Helier";
+    private const string JERSEY_OFFICIAL_NAME = "Bailiwick of Jersey";
+    private const string JERSEY_ISO2_CODE = "JE";
+    private const string JERSEY_ISO3_CODE = "JEY";
+    private const int JERSEY_NUMERIC_CODE = 832;
+    private readonly string[] JERSEY_CALLING_CODE = ["+44"];
+    private const int JERSEY_STATE_COUNT = 12;
+    private static readonly string[] VALID_STATE_TYPES = { "parish" };
+
+    [Fact]
+    public void GetCountry_ReturnsCorrectInformation_ForJersey()
+    {
+        // Arrange
+        CountryIdentifier existingCountryId = CountryIdentifier.Jersey;
+
+        // Act
+        var country = CountryProvider.GetCountry(existingCountryId);
+
+        // Assert
+        Assert.NotNull(country);
+        Assert.Equal(existingCountryId, country.Id);
+        Assert.Equal(JERSEY_COUNTRY_NAME, country.Name);
+        Assert.Equal(JERSEY_OFFICIAL_NAME, country.OfficialName);
+        Assert.Equal(JERSEY_NATIVE_NAME, country.NativeName);
+        Assert.Equal(JERSEY_CAPITAL, country.Capital);
+        Assert.Equal(JERSEY_NUMERIC_CODE, country.NumericCode);
+        Assert.Equal(JERSEY_ISO2_CODE, country.ISO2Code);
+        Assert.Equal(JERSEY_ISO3_CODE, country.ISO3Code);
+        Assert.Equal(JERSEY_CALLING_CODE, country.CallingCode);
+        Assert.NotNull(country.States);
+        Assert.Equal(JERSEY_STATE_COUNT, country.States.Count());
+        Assert.All(country.States, state => Assert.Contains(state.Type, VALID_STATE_TYPES));
+    }
+}
diff --git a/src/World.Net.UnitTests/Countries/JordanTest.cs b/src/World.Net.UnitTests/Countries/JordanTest.cs
new file mode 100644
index 0000000..4c383d7
--- /dev/null
+++ b/src/World.Net.UnitTests/Countries/JordanTest.cs
@@ -0,0 +1,39 @@
+namespace World.Net.UnitTests.Countries;
+public sealed class JordanTest
+{
+    private const string JORDAN_COUNTRY_NAME = "Jordan";
+    private const string JORDAN_NATIVE_NAME = "الأردن";
+    private const string JORDAN_CAPITAL = "Amman";
+    private const string JORDAN_OFFICIAL_NAME = "Hashemite Kingdom of Jordan";
+    private const string JORDAN_ISO2_CODE = "JO";
+    private const string JORDAN_ISO3_CODE = "JOR";
+    private const int JORDAN_NUMERIC_CODE = 400;
+    private readonly string[] JORDAN_CALLING_CODE = ["+962"];
+    private const int JORDAN_STATE_COUNT = 12;
+    private static readonly string[] VALID_STATE_TYPES = { "governorate" };
+
+    [Fact]
+    public void GetCountry_ReturnsCorrectInformation_ForJordan()
+    {
+        // Arrange
+        CountryIdentifier existingCountryId = CountryIdentifier.Jordan;
+
+        // Act
+        var country = CountryProvider.GetCountry(existingCountryId);
+
+        // Assert
+        Assert.NotNull(country);
+        Assert.Equal(existingCountryId, country.Id);
+        Assert.Equal(JORDAN_COUNTRY_NAME, country.Name);
+        Assert.Equal(JORDAN_OFFICIAL_NAME, country.OfficialName);
+        Assert.Equal(JORDAN_NATIVE_NAME, country.NativeName);
+        Assert.Equal(JORDAN_CAPITAL, country.Capital);
+        Assert.Equal(JORDAN_NUMERIC_CODE, country.NumericCode);
+        Assert.Equal(JORDAN_ISO2_CODE, country.ISO2Code);
+        Assert.Equal(JORDAN_ISO3_CODE, country.ISO3Code);
+        Assert.Equal(JORDAN_CALLING_CODE, country.CallingCode);
+        Assert.NotNull(country.States);
+        Assert.Equal(JORDAN_STATE_COUNT, country.States.Count());
+        Assert.All(country.States, state => Assert.Contains(state.Type, VALID_STATE_TYPES));
+    }
+}
diff --git a/src/World.Net/Countries/Jamaica.cs b/src/World.Net/Countries/Jamaica.cs
new file mode 100644
index 0000000..7a5365e
--- /dev/null
+++ b/src/World.Net/Countries/Jamaica.cs
@@ -0,0 +1,48 @@
+namespace World.Net.Countries;
+internal sealed class Jamaica : ICountry
+{
+    public CountryIdentifier Id => CountryIdentifier.Jamaica;
+
+    //<inheritdoc/>
+    public string Name { get; } = "Jamaica";
+
+    //<inheritdoc/>
+    public string OfficialName { get; } = "Jamaica";
+
+    //<inheritdoc/>
+    public string NativeName => "Jamaica";
+
+    //<inheritdoc/>
+    public string Capital { get; } = "Kingston";
+
+    //<inheritdoc/>
+    public int NumericCode { get; } = 388;
+
+    //<inheritdoc/>
+    public string ISO2Code { get; } = "JM";
+
+    //<inheritdoc/>
+    public string ISO3Code { get; } = "JAM";
+
+    //<inheritdoc/>
+    public string[] CallingCode { get; } = ["+1-876"];
+
+    //<inheritdoc/>
+    public IEnumerable<State> States =>
+    [
+        new("Clarendon", "JM-13", "Parish"),
+        new("Hanover", "JM-09", "Parish"),
+        new("Kingston", "JM-01", "Parish"),
+        new("Manchester", "JM-12", "Parish"),
+        new("Portland", "JM-04", "Parish"),
+        new("Saint Andrew", "JM-02", "Parish"),
+        new("Saint Ann", "JM-06", "Parish"),
+        new("Saint Catherine", "JM-14", "Parish"),
+        new("Saint Elizabeth", "JM-11", "Parish"),
+        new("Saint James", "JM-08", "Parish"),
+        new("Saint Mary", "JM-05", "Parish"),
+        new("Saint Thomas", "JM-03", "Parish"),
+        new("Trelawny", "JM-07", "Parish"),
+        new("Westmoreland", "JM-10", "Parish"),
+    ];
+}
diff --git a/src/World.Net/Countries/Japan.cs b/src/World.Net/Countries/Japan.cs
new file mode 100644
index 0000000..59689d4
--- /dev/null
+++ b/src/World.Net/Countries/Japan.cs
@@ -0,0 +1,82 @@
+namespace World.Net.Countries;
+internal sealed class Japan : ICountry
+{
+    public CountryIdentifier Id => CountryIdentifier.Japan;
+
+    //<inheritdoc/>
+    public string Name { get; } = "Japan";
+
+    //<inheritdoc/>
+    public string OfficialName { get; } = "Japan";
+
+    //<inheritdoc/>
+    public string NativeName => "日本";
+
+    //<inheritdoc/>
+    public string Capital { get; } = "Tokyo";
+
+    //<inheritdoc/>
+    public int NumericCode { get; } = 392;
+
+    //<inheritdoc/>
+    public string ISO2Code { get; } = "JP";
+
+    //<inheritdoc/>
+    public string ISO3Code { get; } = "JPN";
+
+    //<inheritdoc/>
+    public string[] CallingCode { get; } = ["+81"];
+
+    //<inheritdoc/>
+    public IEnumerable<State> States =>
+    [
+        new("Aichi", "JP-23", "Prefecture"),
+        new("Akita", "JP-05", "Prefecture"),
+        new("Aomori", "JP-02", "Prefecture"),
+        new("Chiba", "JP-12", "Prefecture"),
+        new("Ehime", "JP-38", "Prefecture"),
+        new("Fukui", "JP-18", "Prefecture"),
+        new("Fukuoka", "JP-40", "Prefecture"),
+        new("Fukushima", "JP-07", "Prefecture"),
+        new("Gifu", "JP-21", "Prefecture"),
+        new("Gunma", "JP-10", "Prefecture"),
+        new("Hiroshima", "JP-34", "Prefecture"),
+        new("Hokkaidō", "JP-01", "Prefecture"),
+        new("Hyōgo", "JP-28", "Prefecture"),
+        new("Ibaraki", "JP-08", "Prefecture"),
+        new("Ishikawa", "JP-17", "Prefecture"),
+        new("Iwate", "JP-03", "Prefecture"),
+        new("Kagawa", "JP-37", "Prefecture"),
+        new("Kagoshima", "JP-46", "Prefecture"),
+        new("Kanagawa", "JP-14", "Prefecture"),
+        new("Kōchi", "JP-39", "Prefecture"),
+        new("Kumamoto", "JP-43", "Prefecture"),
+        new("Kyōto", "JP-26", "Prefecture"),
+        new("Mie", "JP-24", "Prefecture"),
+        new("Miyagi", "JP-04", "Prefecture"),
+        new("Miyazaki", "JP-45", "Prefecture"),
+        new("Nagano", "JP-20", "Prefecture"),
+        new("Nagasaki", "JP-42", "Prefecture"),
+        new("Nara", "JP-29", "Prefecture"),
+        new("Niigata", "JP-15", "Prefecture"),
+        new("Ōita", "JP-44", "Prefecture"),
+        new("Okayama", "JP-33", "Prefecture"),
+        new("Okinawa", "JP-47", "Prefecture"),
+        new("Ōsaka", "JP-27", "Prefecture"),
+        new("Saga", "JP-41", "Prefecture"),
+        new("Saitama", "JP-11", "Prefecture"),
+        new("Shiga", "JP-25", "Prefecture"),
+        new("Shimane", "JP-32", "Prefecture"),
+        new("Shizuoka", "JP-22", "Prefecture"),
+        new("Tochigi", "JP-09", "Prefecture"),
+        new("Tokushima", "JP-36", "Prefecture"),
+        new("Tokyo", "JP-13", "Prefecture"),
+        new("Tottori", "JP-31", "Prefecture"),
+        new("Toyama", "JP-16", "Prefecture"),
+        new("Wakayama", "JP-30", "Prefecture"),
+        new("Yamagata", "JP-06", "Prefecture"),
+        new("Yamaguchi", "JP-35", "Prefecture"),
+        new("Yamanashi", "JP-19", "Prefecture"),
+
+    ];
+}
diff --git a/src/World.Net/Countries/Jersey.cs b/src/World.Net/Countries/Jersey.cs
new file mode 100644
index 0000000..ca7847c
--- /dev/null
+++ b/src/World.Net/Countries/Jersey.cs
@@ -0,0 +1,46 @@
+namespace World.Net.Countries;
+internal sealed class Jersey : ICountry
+{
+    public CountryIdentifier Id => CountryIdentifier.Jersey;
+
+    //<inheritdoc/>
+    public string Name { get; } = "Jersey";
+
+    //<inheritdoc/>
+    public string OfficialName { get; } = "Bailiwick of Jersey";
+
+    //<inheritdoc/>
+    public string NativeName => "Jersey";
+
+    //<inheritdoc/>
+    public string Capital { get; } = "Saint Helier";
+
+    //<inheritdoc/>
+    public int NumericCode { get; } = 832;
+
+    //<inheritdoc/>
+    public string ISO2Code { get; } = "JE";
+
+    //<inheritdoc/>
+    public string ISO3Code { get; } = "JEY";
+
+    //<inheritdoc/>
+    public string[] CallingCode { get; } = ["+44"];
+
+    //<inheritdoc/>
+    public IEnumerable<State> States =>
+    [
+        new("Grouville", "JE-01", "parish"),
+        new("St Brelade", "JE-02", "parish"),
+        new("St Clement", "JE-03", "parish"),
+        new("St Helier", "JE-04", "parish"),
+        new("St John", "JE-05", "parish"),
+        new("St Lawrence", "JE-06", "parish"),
+        new("St Martin", "JE-07", "parish"),
+        new("St Mary", "JE-08", "parish"),
+        new("St Ouen", "JE-09", "parish"),
+        new("St Peter", "JE-10", "parish"),
+        new("St Saviour", "JE-11", "parish"),
+        new("Trinity", "JE-12", "parish"),
+    ];
+}
diff --git a/src/World.Net/Countries/Jordan.cs b/src/World.Net/Countries/Jordan.cs
new file mode 100644
index 0000000..fd6d8f4
--- /dev/null
+++ b/src/World.Net/Countries/Jordan.cs
@@ -0,0 +1,46 @@
+namespace World.Net.Countries;
+internal sealed class Jordan : ICountry
+{
+    public CountryIdentifier Id => CountryIdentifier.Jordan;
+
+    //<inheritdoc/>
+    public string Name { get; } = "Jordan";
+
+    //<inheritdoc/>
+    public string OfficialName { get; } = "Hashemite Kingdom of Jordan";
+
+    //<inheritdoc/>
+    public string NativeName => "الأردن";
+
+    //<inheritdoc/>
+    public string Capital { get; } = "Amman";
+
+    //<inheritdoc/>
+    public int NumericCode { get; } = 400;
+
+    //<inheritdoc/>
+    public string ISO2Code { get; } = "JO";
+
+    //<inheritdoc/>
+    public string ISO3Code { get; } = "JOR";
+
+    //<inheritdoc/>
+    public string[] CallingCode { get; } = ["+962"];
+
+    //<inheritdoc/>
+    public IEnumerable<State> States =>
+    [
+        new("Ajloun", "JO-AJ", "governorate"),
+        new("Amman", "JO-AM", "governorate"),
+        new("Aqaba", "JO-AQ", "governorate"),
+        new("Balqa", "JO-BA", "governorate"),
+        new("Irbid", "JO-IR", "governorate"),
+        new("Jerash", "JO-JA", "governorate"),
+        new("Karak", "JO-KA", "governorate"),
+        new("Ma'an", "JO-MN", "governorate"),
+        new("Madaba", "JO-MD", "governorate"),
+        new("Mafraq", "JO-MA", "governorate"),
+        new("Tafilah", "JO-AT", "governorate"),
+        new("Zarqa", "JO-AZ", "governorate"),
+    ];
+}
diff --git a/src/World.Net/Helpers/CountryInitializer.cs b/src/World.Net/Helpers/CountryInitializer.cs
index ba11d9e..673508c 100644
--- a/src/World.Net/Helpers/CountryInitializer.cs
+++ b/src/World.Net/Helpers/CountryInitializer.cs
@@ -88,6 +88,10 @@ public static Dictionary<CountryIdentifier, ICountry> Initialize()
             { CountryIdentifier.Ireland, new Ireland() },
             { CountryIdentifier.Israel, new Israel() },
             { CountryIdentifier.Italy, new Italy() },
+            { CountryIdentifier.Jamaica, new Jamaica() },
+            { CountryIdentifier.Japan, new Japan() },
+            { CountryIdentifier.Jersey, new Jersey() },
+            { CountryIdentifier.Jordan, new Jordan() }      
 
             // Future countries can be added here in the same format.
         };