fɹʌm tˈuː θˈaʊzənd fˈaɪv ʌntˈɪl ɪts ɹᵻplˈeɪsmənt baɪ sˌiːdˌiːsˈiː ˌɛnˌɛsdˈʌbəljˌuː ɪn tˈuː θˈaʊzənd twˈɛnti θɹˈiː, hˈɪlsbəs sˈɜːvɪsᵻz hæd fˈɔːɹmd sˈɪdni bˈʌs ɹˈiːdʒən fˈoːɹ.
From 2005 until its replacement by CDC NSW in 2023, Hillsbus' services had formed Sydney Bus Region 4.