diff --git a/packages/i18nify-go/example/example.go b/packages/i18nify-go/example/example.go
index ce81882b..d836da18 100644
--- a/packages/i18nify-go/example/example.go
+++ b/packages/i18nify-go/example/example.go
@@ -36,6 +36,7 @@ func main() {
 	fmt.Println(state.GetCities()[0]) //{Yellāpur nan Asia/Kolkata [581337 581337 ...}
 
 	// Get States by zipcode
+	// As suggested online there are some cases in which one zipcode can be
 	madhyaPradesh := countryIN.GetStatesByZipCode("452010")[0]
 	fmt.Printf("For pincode 452010 state : %s\n", madhyaPradesh) // {[{Wārāseonī nan Asia/Kolkata [481331 ...}
 	fmt.Printf("State name %s\n", madhyaPradesh.GetName())
diff --git a/packages/i18nify-go/modules/country_subdivisions/country_subdivisions.go b/packages/i18nify-go/modules/country_subdivisions/country_subdivisions.go
index da0ede23..4a067533 100644
--- a/packages/i18nify-go/modules/country_subdivisions/country_subdivisions.go
+++ b/packages/i18nify-go/modules/country_subdivisions/country_subdivisions.go
@@ -58,11 +58,8 @@ func (r *CountrySubdivisions) GetStateByStateCode(code string) (State, bool) {
 
 func (r *CountrySubdivisions) GetCityDetailsByCityName(cityName string, stateCode string) (City, bool) {
 	if state, exists := r.States[stateCode]; exists {
-		for _, city := range state.Cities {
-			if city.Name == cityName {
-				return city, true
-			}
-		}
+		city, exists := state.Cities[cityName]
+		return city, exists
 	}
 	return City{}, false
 }
@@ -96,13 +93,17 @@ func NewCountrySubdivisions(countryName string, states map[string]State) *Countr
 
 // State contains information about a state or province.
 type State struct {
-	Cities []City `json:"cities"` // Cities contains information about cities within the state.
-	Name   string `json:"name"`   // Name represents the name of the state.
+	Cities map[string]City `json:"cities"` // Cities contains information about cities within the state.
+	Name   string          `json:"name"`   // Name represents the name of the state.
 }
 
 // GetCities returns information about cities within the state.
 func (r *State) GetCities() []City {
-	return r.Cities
+	cities := make([]City, 0, len(r.Cities))
+	for _, city := range r.Cities {
+		cities = append(cities, city)
+	}
+	return cities
 }
 
 // GetName returns the name of the state.
@@ -110,8 +111,33 @@ func (r *State) GetName() string {
 	return r.Name
 }
 
+// UnmarshalJSON Custom unmarshal for States
+func (r *State) UnmarshalJSON(data []byte) error {
+	// Temporary structure to unmarshal cities as a slice
+	type Temp State
+	temp := &struct {
+		Cities []City `json:"cities"`
+		*Temp
+	}{
+		Temp: (*Temp)(r),
+	}
+
+	// Unmarshal into temporary struct
+	if err := json.Unmarshal(data, &temp); err != nil {
+		return err
+	}
+
+	// Convert the slice of cities into a map
+	r.Cities = make(map[string]City)
+	for _, city := range temp.Cities {
+		r.Cities[city.Name] = city
+	}
+
+	return nil
+}
+
 // NewState creates a new State instance.
-func NewState(cities []City, name string) *State {
+func NewState(cities map[string]City, name string) *State {
 	return &State{
 		Cities: cities,
 		Name:   name,
diff --git a/packages/i18nify-go/modules/country_subdivisions/country_subdivisions_test.go b/packages/i18nify-go/modules/country_subdivisions/country_subdivisions_test.go
index e717db0f..02c7f70c 100644
--- a/packages/i18nify-go/modules/country_subdivisions/country_subdivisions_test.go
+++ b/packages/i18nify-go/modules/country_subdivisions/country_subdivisions_test.go
@@ -31,8 +31,8 @@ func TestMarshalCountrySubdivisions(t *testing.T) {
 		CountryName: "India",
 		States: map[string]State{
 			"KA": {
-				Cities: []City{
-					{Name: "Bengaluru", RegionName: "nan", Timezone: "Asia/Kolkata", Zipcodes: []string{"560018", "560116", "560500"}},
+				Cities: map[string]City{
+					"Bengaluru": {Name: "Bengaluru", RegionName: "nan", Timezone: "Asia/Kolkata", Zipcodes: []string{"560018", "560116", "560500"}},
 				},
 				Name: "Karnataka",
 			},
@@ -109,16 +109,16 @@ func TestGetCityByCityNameAndStateCode(t *testing.T) {
 		States: map[string]State{
 			"KA": {
 				Name: "Karnataka",
-				Cities: []City{
-					{Name: "Bengaluru", Timezone: "Asia/Kolkata", Zipcodes: []string{"560018", "560116"}},
-					{Name: "Mysore", Timezone: "Asia/Kolkata", Zipcodes: []string{"570001"}},
+				Cities: map[string]City{
+					"Bengaluru": {Name: "Bengaluru", Timezone: "Asia/Kolkata", Zipcodes: []string{"560018", "560116"}},
+					"Mysore":    {Name: "Mysore", Timezone: "Asia/Kolkata", Zipcodes: []string{"570001"}},
 				},
 			},
 			"MH": {
 				Name: "Maharashtra",
-				Cities: []City{
-					{Name: "Mumbai", Timezone: "Asia/Kolkata", Zipcodes: []string{"400001"}},
-					{Name: "Pune", Timezone: "Asia/Kolkata", Zipcodes: []string{"411001"}},
+				Cities: map[string]City{
+					"Mumbai": {Name: "Mumbai", Timezone: "Asia/Kolkata", Zipcodes: []string{"400001"}},
+					"Pune":   {Name: "Pune", Timezone: "Asia/Kolkata", Zipcodes: []string{"411001"}},
 				},
 			},
 		},