diff --git a/src/World.Net.UnitTests/Countries/CongoTest.cs b/src/World.Net.UnitTests/Countries/CongoTest.cs
new file mode 100644
index 0000000..a54da45
--- /dev/null
+++ b/src/World.Net.UnitTests/Countries/CongoTest.cs
@@ -0,0 +1,39 @@
+namespace World.Net.UnitTests.Countries
+{
+    public sealed class CongoTest
+    {
+        private const string CONGO_NAME = "Congo";
+        private const int CONGO_STATE_COUNT = 12;
+        private const string CONGO_OFFICIAL_NAME = "Democratic Republic of the Congo";
+        private const string CONGO_NATIVE_NAME = "République du Congo";
+        private const string CONGO_CAPITAL = "Brazzaville";
+        private const int CONGO_NUMERIC_CODE = 178;
+        private const string CONGO_ISO2_CODE = "CG";
+        private const string CONGO_ISO3_CODE = "COG";
+        private const string CONGO_CALLING_CODE = "+242";
+
+
+        [Fact]
+        public void GetCountry_ReturnsCorrectInformation_ForCongo()
+        {
+            // Arrange
+            CountryIdentifier existingCountryId = CountryIdentifier.Congo;
+
+            // Act
+            var country = CountryProvider.GetCountry(existingCountryId);
+
+            //Assert
+            Assert.Equal(existingCountryId, country.Id);
+            Assert.Equal(CONGO_NAME, country.Name);
+            Assert.NotNull(country.States);
+            Assert.Equal(CONGO_STATE_COUNT, country.States.Count());
+            Assert.Equal(CONGO_OFFICIAL_NAME, country.OfficialName);
+            Assert.Equal(CONGO_NATIVE_NAME, country.NativeName);
+            Assert.Equal(CONGO_CAPITAL, country.Capital);
+            Assert.Equal(CONGO_NUMERIC_CODE, country.NumericCode);
+            Assert.Equal(CONGO_ISO2_CODE, country.ISO2Code);
+            Assert.Equal(CONGO_ISO3_CODE, country.ISO3Code);
+            Assert.Equal(CONGO_CALLING_CODE, country.CallingCode);
+        }
+    }
+}
diff --git a/src/World.Net.UnitTests/Countries/CookIslandsTest.cs b/src/World.Net.UnitTests/Countries/CookIslandsTest.cs
new file mode 100644
index 0000000..2e4f1cb
--- /dev/null
+++ b/src/World.Net.UnitTests/Countries/CookIslandsTest.cs
@@ -0,0 +1,38 @@
+namespace World.Net.UnitTests.Countries
+{
+    public sealed class CookIslandsTest
+    {
+        private const string COOKISLANDS_NAME = "Cook Islands";
+        private const string COOKISLANDS_OFFICIAL_NAME = "Cook Islands";
+        private const string COOKISLANDS_NATIVE_NAME = "Cook Islands";
+        private const string COOKISLANDS_CAPITAL = "Avarua";
+        private const int COOKISLANDS_NUMERIC_CODE = 184;
+        private const string COOKISLANDS_ISO2_CODE = "CK";
+        private const string COOKISLANDS_ISO3_CODE = "COK";
+        private const string COOKISLANDS_CALLING_CODE = "+682";
+
+
+        [Fact]
+        public void GetCountry_ReturnsCorrectInformation_ForCookIslands()
+        {
+            // Arrange
+            CountryIdentifier existingCountryId = CountryIdentifier.CookIslands;
+
+            // Act
+            var country = CountryProvider.GetCountry(existingCountryId);
+
+            //Assert
+            Assert.Equal(existingCountryId, country.Id);
+            Assert.Equal(COOKISLANDS_NAME, country.Name);
+            Assert.NotNull(country.States);
+            Assert.Empty(country.States);
+            Assert.Equal(COOKISLANDS_OFFICIAL_NAME, country.OfficialName);
+            Assert.Equal(COOKISLANDS_NATIVE_NAME, country.NativeName);
+            Assert.Equal(COOKISLANDS_CAPITAL, country.Capital);
+            Assert.Equal(COOKISLANDS_NUMERIC_CODE, country.NumericCode);
+            Assert.Equal(COOKISLANDS_ISO2_CODE, country.ISO2Code);
+            Assert.Equal(COOKISLANDS_ISO3_CODE, country.ISO3Code);
+            Assert.Equal(COOKISLANDS_CALLING_CODE, country.CallingCode);
+        }
+    }
+}
diff --git a/src/World.Net.UnitTests/Countries/CostaRicaTest.cs b/src/World.Net.UnitTests/Countries/CostaRicaTest.cs
new file mode 100644
index 0000000..c69d673
--- /dev/null
+++ b/src/World.Net.UnitTests/Countries/CostaRicaTest.cs
@@ -0,0 +1,39 @@
+namespace World.Net.UnitTests.Countries
+{
+    public sealed class CostaRicaTest
+    {
+        private const string COSTARICA_NAME = "Costa Rica";
+        private const int COSTARICA_STATE_COUNT = 7;
+        private const string COSTARICA_OFFICIAL_NAME = "Republic of Costa Rica";
+        private const string COSTARICA_NATIVE_NAME = "Costa Rica";
+        private const string COSTARICA_CAPITAL = "San Jose";
+        private const int COSTARICA_NUMERIC_CODE = 188;
+        private const string COSTARICA_ISO2_CODE = "CR";
+        private const string COSTARICA_ISO3_CODE = "CRI";
+        private const string COSTARICA_CALLING_CODE = "+506";
+
+
+        [Fact]
+        public void GetCountry_ReturnsCorrectInformation_ForCostaRica()
+        {
+            // Arrange
+            CountryIdentifier existingCountryId = CountryIdentifier.CostaRica;
+
+            // Act
+            var country = CountryProvider.GetCountry(existingCountryId);
+
+            //Assert
+            Assert.Equal(existingCountryId, country.Id);
+            Assert.Equal(COSTARICA_NAME, country.Name);
+            Assert.NotNull(country.States);
+            Assert.Equal(COSTARICA_STATE_COUNT, country.States.Count());
+            Assert.Equal(COSTARICA_OFFICIAL_NAME, country.OfficialName);
+            Assert.Equal(COSTARICA_NATIVE_NAME, country.NativeName);
+            Assert.Equal(COSTARICA_CAPITAL, country.Capital);
+            Assert.Equal(COSTARICA_NUMERIC_CODE, country.NumericCode);
+            Assert.Equal(COSTARICA_ISO2_CODE, country.ISO2Code);
+            Assert.Equal(COSTARICA_ISO3_CODE, country.ISO3Code);
+            Assert.Equal(COSTARICA_CALLING_CODE, country.CallingCode);
+        }
+    }
+}
diff --git a/src/World.Net.UnitTests/Countries/CoteDIvoireTest.cs b/src/World.Net.UnitTests/Countries/CoteDIvoireTest.cs
new file mode 100644
index 0000000..e7a6c19
--- /dev/null
+++ b/src/World.Net.UnitTests/Countries/CoteDIvoireTest.cs
@@ -0,0 +1,39 @@
+namespace World.Net.UnitTests.Countries
+{
+    public sealed class CoteDIvoireTest
+    {
+        private const string COTEDIVOIRE_NAME = "Ivory Coast";
+        private const int COTEDIVOIRE_STATE_COUNT = 31;
+        private const string COTEDIVOIRE_OFFICIAL_NAME = "Republic of Côte d'Ivoire";
+        private const string COTEDIVOIRE_NATIVE_NAME = "Côte d'Ivoire";
+        private const string COTEDIVOIRE_CAPITAL = "Yamoussoukro";
+        private const int COTEDIVOIRE_NUMERIC_CODE = 384;
+        private const string COTEDIVOIRE_ISO2_CODE = "CI";
+        private const string COTEDIVOIRE_ISO3_CODE = "CIV";
+        private const string COTEDIVOIRE_CALLING_CODE = "+225";
+
+
+        [Fact]
+        public void GetCountry_ReturnsCorrectInformation_ForCookIslands()
+        {
+            // Arrange
+            CountryIdentifier existingCountryId = CountryIdentifier.CoteDIvoire;
+
+            // Act
+            var country = CountryProvider.GetCountry(existingCountryId);
+
+            //Assert
+            Assert.Equal(existingCountryId, country.Id);
+            Assert.Equal(COTEDIVOIRE_NAME, country.Name);
+            Assert.NotNull(country.States);
+            Assert.Equal(COTEDIVOIRE_STATE_COUNT, country.States.Count());
+            Assert.Equal(COTEDIVOIRE_OFFICIAL_NAME, country.OfficialName);
+            Assert.Equal(COTEDIVOIRE_NATIVE_NAME, country.NativeName);
+            Assert.Equal(COTEDIVOIRE_CAPITAL, country.Capital);
+            Assert.Equal(COTEDIVOIRE_NUMERIC_CODE, country.NumericCode);
+            Assert.Equal(COTEDIVOIRE_ISO2_CODE, country.ISO2Code);
+            Assert.Equal(COTEDIVOIRE_ISO3_CODE, country.ISO3Code);
+            Assert.Equal(COTEDIVOIRE_CALLING_CODE, country.CallingCode);
+        }
+    }
+}
diff --git a/src/World.Net/Countries/Congo.cs b/src/World.Net/Countries/Congo.cs
new file mode 100644
index 0000000..6e37a74
--- /dev/null
+++ b/src/World.Net/Countries/Congo.cs
@@ -0,0 +1,49 @@
+namespace World.Net.Countries
+{
+    internal sealed class Congo : ICountry
+    {
+        ///<inheritdoc/>
+        public CountryIdentifier Id => CountryIdentifier.Congo;
+
+        ///<inheritdoc/>
+        public string Name => nameof(Congo);
+
+        ///<inheritdoc/>
+        public string OfficialName { get; } = "Democratic Republic of the Congo";
+
+        ///<inheritdoc/>
+        public string NativeName { get; } = "République du Congo";
+
+        ///<inheritdoc/>
+        public string Capital { get; } = "Brazzaville";
+
+        ///<inheritdoc/>
+        public int NumericCode { get; } = 178;
+
+        ///<inheritdoc/>
+        public string ISO2Code { get; } = "CG";
+
+        ///<inheritdoc/>
+        public string ISO3Code { get; } = "COG";
+
+        ///<inheritdoc/>
+        public string CallingCode { get; } = "+242";
+
+        ///<inheritdoc/>
+        public IEnumerable<State> States { get; } =
+        [
+            new("Bouenza", "CG-11", "Department"),
+            new("Brazzaville", "CG-BZV", "Department"),
+            new("Cuvette", "CG-8", "Department"),
+            new("Cuvette-Ouest", "CG-15", "Department"),
+            new("Kouilou", "CG-5", "Department"),
+            new("Lékoumou", "CG-2", "Department"),
+            new("Likouala", "CG-7", "Department"),
+            new("Niari", "CG-9", "Department"),
+            new("Plateaux", "CG-14", "Department"),
+            new("Pointe-Noire", "CG-16", "Department"),
+            new("Pool", "CG-12", "Department"),
+            new("Sangha", "CG-13", "Department"),
+        ];
+    }
+}
diff --git a/src/World.Net/Countries/CookIslands.cs b/src/World.Net/Countries/CookIslands.cs
new file mode 100644
index 0000000..b2c1104
--- /dev/null
+++ b/src/World.Net/Countries/CookIslands.cs
@@ -0,0 +1,35 @@
+namespace World.Net.Countries
+{
+    internal sealed class CookIslands : ICountry
+    {
+        ///<inheritdoc/>
+        public CountryIdentifier Id => CountryIdentifier.CookIslands;
+
+        ///<inheritdoc/>
+        public string Name => "Cook Islands";
+
+        ///<inheritdoc/>
+        public string OfficialName { get; } = "Cook Islands";
+
+        ///<inheritdoc/>
+        public string NativeName { get; } = "Cook Islands";
+
+        ///<inheritdoc/>
+        public string Capital { get; } = "Avarua";
+
+        ///<inheritdoc/>
+        public int NumericCode { get; } = 184;
+
+        ///<inheritdoc/>
+        public string ISO2Code { get; } = "CK";
+
+        ///<inheritdoc/>
+        public string ISO3Code { get; } = "COK";
+
+        ///<inheritdoc/>
+        public string CallingCode { get; } = "+682";
+
+        ///<inheritdoc/>
+        public IEnumerable<State> States { get; } = [];
+    }
+}
diff --git a/src/World.Net/Countries/CostaRica.cs b/src/World.Net/Countries/CostaRica.cs
new file mode 100644
index 0000000..b947951
--- /dev/null
+++ b/src/World.Net/Countries/CostaRica.cs
@@ -0,0 +1,44 @@
+namespace World.Net.Countries
+{
+    internal sealed class CostaRica : ICountry
+    {
+        ///<inheritdoc/>
+        public CountryIdentifier Id => CountryIdentifier.CostaRica;
+
+        ///<inheritdoc/>
+        public string Name => "Costa Rica";
+
+        ///<inheritdoc/>
+        public string OfficialName { get; } = "Republic of Costa Rica";
+
+        ///<inheritdoc/>
+        public string NativeName { get; } = "Costa Rica";
+
+        ///<inheritdoc/>
+        public string Capital { get; } = "San Jose";
+
+        ///<inheritdoc/>
+        public int NumericCode { get; } = 188;
+
+        ///<inheritdoc/>
+        public string ISO2Code { get; } = "CR";
+
+        ///<inheritdoc/>
+        public string ISO3Code { get; } = "CRI";
+
+        ///<inheritdoc/>
+        public string CallingCode { get; } = "+506";
+
+        ///<inheritdoc/>
+        public IEnumerable<State> States { get; } =
+        [
+            new("Alajuela", "CR-A", "Province"),
+            new("Cartago", "CR-C", "Province"),
+            new("Guanacaste", "CR-G", "Province"),
+            new("Heredia", "CR-H", "Province"),
+            new("Limón", "CR-L", "Province"),
+            new("Puntarenas", "CR-P", "Province"),
+            new("San José", "CR-SJ", "Province"),
+        ];
+    }
+}
diff --git a/src/World.Net/Countries/CoteD'Ivoire.cs b/src/World.Net/Countries/CoteD'Ivoire.cs
new file mode 100644
index 0000000..a930e54
--- /dev/null
+++ b/src/World.Net/Countries/CoteD'Ivoire.cs
@@ -0,0 +1,68 @@
+namespace World.Net.Countries
+{
+    internal sealed class CoteDIvoire : ICountry
+    {
+        ///<inheritdoc/>
+        public CountryIdentifier Id => CountryIdentifier.CoteDIvoire;
+
+        ///<inheritdoc/>
+        public string Name => "Ivory Coast";
+
+        ///<inheritdoc/>
+        public string OfficialName { get; } = "Republic of Côte d'Ivoire";
+
+        ///<inheritdoc/>
+        public string NativeName { get; } = "Côte d'Ivoire";
+
+        ///<inheritdoc/>
+        public string Capital { get; } = "Yamoussoukro";
+
+        ///<inheritdoc/>
+        public int NumericCode { get; } = 384;
+
+        ///<inheritdoc/>
+        public string ISO2Code { get; } = "CI";
+
+        ///<inheritdoc/>
+        public string ISO3Code { get; } = "CIV";
+
+        ///<inheritdoc/>
+        public string CallingCode { get; } = "+225";
+
+        ///<inheritdoc/>
+        public IEnumerable<State> States { get; } =
+        [
+            new("Abidjan", "CI-AB", "Autonomous District"),
+            new("Agnéby", "CI-16", "Region"),
+            new("Bafing", "CI-17", "Region"),
+            new("Bas-Sassandra", "CI-BS", "District"),
+            new("Bas-Sassandra", "CI-09", "Region"),
+            new("Comoé", "CI-CM", "District"),
+            new("Denguélé", "CI-DN", "District"),
+            new("Denguélé", "CI-10", "Region"),
+            new("Dix-Huit Montagnes", "CI-06", "Region"),
+            new("Fromager", "CI-18", "Region"),
+            new("Gôh-Djiboua", "CI-GD", "District"),
+            new("Haut-Sassandra", "CI-02", "Region"),
+            new("Lacs", "CI-07", "Region"),
+            new("Lacs", "CI-LC", "District"),
+            new("Lagunes", "CI-01", "Region"),
+            new("Lagunes", "CI-LG", "District"),
+            new("Marahoué", "CI-12", "Region"),
+            new("Montagnes", "CI-MG", "District"),
+            new("Moyen-Cavally", "CI-19", "Region"),
+            new("Moyen-Comoé", "CI-05", "Region"),
+            new("N'zi-Comoé", "CI-11", "Region"),
+            new("Sassandra-Marahoué", "CI-SM", "District"),
+            new("Savanes", "CI-03", "Region"),
+            new("Sud-Bandama", "CI-15", "Region"),
+            new("Sud-Comoé", "CI-13", "Region"),
+            new("Vallée du Bandama", "CI-04", "Region"),
+            new("Vallée du Bandama", "CI-VB", "District"),
+            new("Woroba", "CI-WR", "District"),
+            new("Worodougou", "CI-14", "Region"),
+            new("Yamoussoukro", "CI-YM", "District"),
+            new("Zanzan", "CI-ZZ", "District"),
+        ];
+    }
+}
diff --git a/src/World.Net/Helpers/CountryInitializer.cs b/src/World.Net/Helpers/CountryInitializer.cs
index 5caf1ec..528dec8 100644
--- a/src/World.Net/Helpers/CountryInitializer.cs
+++ b/src/World.Net/Helpers/CountryInitializer.cs
@@ -55,6 +55,10 @@ public static Dictionary<CountryIdentifier, ICountry> Initialize()
             { CountryIdentifier.CocosKeelingIslands, new CocosKeelingIslands() },
             { CountryIdentifier.Colombia, new Colombia() },
             { CountryIdentifier.Comoros, new Comoros() },
+            { CountryIdentifier.Congo, new Congo() },
+            { CountryIdentifier.CostaRica, new CostaRica() },
+            { CountryIdentifier.CookIslands, new CookIslands() },
+            { CountryIdentifier.CoteDIvoire, new CoteDIvoire() },
             { CountryIdentifier.Croatia, new Croatia() },
             { CountryIdentifier.Cuba, new Cuba() },
             { CountryIdentifier.Curacao, new Curaçao() },