A VoIP call routing information registry including a hash access mechanism. In particular implementations, a method includes receiving a telephone number; computing a hash of the telephone number; accessing a registry wherein the registry comprises a plurality of entries, and wherein each entry comprises a hash of a telephone number and data associated with that telephone number, or a prefix and data associated with that prefix; searching the registry for a matching entry; and until a matching entry is found or the telephone number has been stripped down to a minimum number of digits, stripping the last digit of the telephone number, re-computing a hash of the stripped-down telephone number, and re-searching the registry for a matching entry.